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Cardiac Hemodynamic

Evaluation: A Manual of Cardiac

Catheterization and

Echocardiography

Omid Salehian MD, MSc, FRCPC

Copyright © O. Salehian, 2002 OmidSalehian

Digitby ODN: SaleDate17:28

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Introduction to Hemodynamics ....................................................................................... 5

A. Role of Cardiac Catheterization in assessment of Cardiac hemodynamics .... 5

B. Cardiac Catheterization Assessment of Normal Hemodynamics..................... 5

a. Right Heart Catheterization............................................................................... 5

b. Left Heart Catheterization................................................................................. 8c. Cardiac output (CO) determination .................................................................. 9

d. Hemodynamic Equations................................................................................. 13

C. Principles of Fluid Dynamics ............................................................................. 14

D. Role of Echocardiography in Assessment of Cardiac Hemodynamics .......... 16

a. Valvular Stenosis.............................................................................................. 17

b. Cardiac output determination by echocardiography ...................................... 18

Indices of Left Ventricular Systolic Function .............................................................. 19

A. Cardiac catheterization ...................................................................................... 19

a. Assessment of LV volume and LVEF ............................................................. 19b. Measurement of LV mass ................................................................................ 20

B. Echocardiography ............................................................................................... 21a. LV mass ............................................................................................................ 21

b. Fractional Shortening ..................................................................................... 22

c. Left ventricular volume and ejection fraction ................................................ 23

d. Velocity of circumferential fiber shortening (Vcf) ......................................... 25

e. The rate of change of LV pressure (dP/dt)...................................................... 26

f. LV wall stress ( σ ).............................................................................................. 27

Diastolic Function and Dysfunction .............................................................................. 28

A. Introduction ......................................................................................................... 28

B. Assessment of LV diastolic function with Cardiac Catheterization............... 29

a. Time constant of ventricular relaxation ( τ ) .................................................... 29

b. Diastolic filling rate (DFR).............................................................................. 30C. Echocardiographic assessment of LV diastolic function ................................. 31

a. Doppler echocardiography .............................................................................. 31

b. Index of myocardial performance ................................................................... 34

c. Time constant of ventricular relaxation ( τ ) .................................................... 34

d. Tissue Doppler imaging (TDI) ........................................................................ 35

e. Color M-mode echocardiography (CMM) ...................................................... 36

Cardiac Tamponade ....................................................................................................... 38

A. Introduction ......................................................................................................... 38

B. Cardiac Catheterization ..................................................................................... 39

C. Echocardiography ............................................................................................... 40

a. RA collapse ........................................................................................................... 41b. RV Diastolic collapse ........................................................................................... 41

c. Respiratory variations in diastolic filling ............................................................ 41

d. IVC plethora......................................................................................................... 42

Constrictive Pericarditis................................................................................................. 43

A. Introduction ......................................................................................................... 43



Restrictive Physiology..................................................................................................... 46



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A. Introduction ......................................................................................................... 46



Valvular Lesions.............................................................................................................. 49

Aortic Stenosis ................................................................................................................. 50

A. Introduction ......................................................................................................... 50B. Cardiac Catheterization ..................................................................................... 50


a. Measurement of gradient ................................................................................. 53b. Valve area determination................................................................................. 54

Aortic Regurgitation ....................................................................................................... 57

A. Introduction ......................................................................................................... 57


a. Acute aortic regurgitation................................................................................ 58

b. Chronic aortic regurgitation............................................................................ 58


a. Assessment of jet area and jet length (Color flow mapping).......................... 60b. LV response to AR............................................................................................ 60

c. M-mode echocardiography .............................................................................. 61e. Flow reversal in descending aorta................................................................... 62

f. Regurgitant volume and fraction .................................................................... 63

Mitral Stenosis................................................................................................................. 64

A. Introduction ......................................................................................................... 64



a. M-mode echocardiography .............................................................................. 67

b. mitral valve gradient ........................................................................................ 67

c. mitral valve area (MVA) .................................................................................. 68

Balloon Mitral Commissurotomy .................................................................................. 71

Mitral Regurgitation....................................................................................................... 76

A. Introduction ......................................................................................................... 76



a. Color flow mapping .......................................................................................... 78b. Vena Contracta ................................................................................................ 78

c. Continuous wave Doppler ................................................................................ 79

d. Volumetric method ........................................................................................... 79

e. Proximal isovelocity surface area method (PISA).......................................... 80

f. Pulmonary vein flow reversal .......................................................................... 81

g. Peak mitral inflow velocity .............................................................................. 81

Tricuspid Valve Disease ................................................................................................. 82

A. Introduction ......................................................................................................... 82



Pulmonic Valve Disease .................................................................................................. 87

A. Introduction ......................................................................................................... 87




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Pulmonary Hypertension ............................................................................................... 92

A. Introduction ......................................................................................................... 92



a. Doppler derived gradients................................................................................ 94b. Other findings (M-mode and 2-D) .................................................................. 96

c. RV isovolumetric relaxation time.................................................................... 96

Intracardiac Shunts ........................................................................................................ 97

A. Introduction ......................................................................................................... 97


a. Oximetric method:................................................................................................ 98

b. Indicator dilution method .................................................................................. 101

C. Echocardiography ............................................................................................. 102

D. Man-made shunts and palliative procedures ................................................. 103

Hypertrophic Cardiomyopathy (HCM)...................................................................... 104

A. Introduction ....................................................................................................... 104B. Cardiac Catheterization ................................................................................... 105

a. Gradients ........................................................................................................ 105b. Percutaneous transluminal septal myocardial ablation (PTSMA) .............. 107

C. Echocardiography ............................................................................................. 108

a. M-mode/2D..................................................................................................... 109

b. Doppler and color flow imaging .................................................................... 109

c. Diastolic filling pattern.................................................................................. 111

Coronary Physiology .................................................................................................... 112

References ...................................................................................................................... 115



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Introduction to Hemodynamics

A. Role of Cardiac Catheterization in assessment of Cardiac hemodynamics

At the turn of the last century, only pulse, respiratory rate, and temperature were

monitored and recorded in patients regardless of severity of illness. It wasn’t untillate 1920s when blood pressure measurements became standard for assessment of

circulatory system. The onset of the electronic revolution in 1960s coincided withthe advent of intensive therapy. First cardiac catheterization by Werner Forssman

in 1929 (on himself), initiated interest in this technique by a small group of

investigators. It wasn’t until the 1950s when this technique gained wide

acceptance and with technological advancements over the years, cardiaccatheterization has a mainstay in both investigation and therapy of patients with

cardiovascular disease.

B. Cardiac Catheterization Assessment of Normal Hemodynamics

The pressure wave created by cardiac muscular contraction is transmitted along a

closed, fluid filled column (catheter) to a pressure transducer. This transducerconverts the mechanical pressure to an electrical signal that can be recorded anddisplayed number of different ways.

a. Right Heart Catheterization

Right heart catheterization allows for measurement and analysis of right atrial

Figure1. Pressuretracings recorded via

a Swan-Ganz catheter

during right heart

catheterization.

(RA) pressures, right ventricular (RV) pressures, pulmonary artery (PA)

pressures, pulmonary capillary wedge pressures (PCWP), cardiac output (CO)determination using thermodilution, assessment for intracardiac shunts,

temporary ventricular pacing, and pulmonary angiography.

i. Right Atrium

The normal RA pressure tracing (Figure 2) is characterized by an a wave (atrial systole), c wave (isovolumetric systole of RV during which thetricuspid valve (TV) is closed), and a v wave (RV systole and filling of RA

from systemic veins and coronary sinus). The x descent follows the a wave

(RA relaxation), following the c wave there is a second pressure declinereferred to as the x’ descent (fall in RA pressure as the RV ejects blood), and

the y descent follows the peak of v wave and begins immediately after the

0

40



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opening of TV. The RA a wave (<8 mmHg) is usually dominant to the v

wave (< 7 mm Hg). The mean RA pressure is normally less than 6 mmHg.

Figure 2. RA pressure tracing in a

normal person. The a wave occurs

simultaneously with atrial

contraction; the v wave occurs duringatrial filling; the c wave is coincident

with the onset of ventricular

contraction; the x descent correspondsto the fall in pressure after atrial

contraction and the continued fall

during early systole ( x’ ); and the y descent occurs after the opening of

the tricuspid valve and with earlydiastolic filling.

ii. Right VentricleThe RV pressure tracing (Figure 3) normally exhibits a peak

systolic pressure equal to the one in main PA and is ≤30 mmHg.

Generally the RA and RV diastolic pressures are equal. The RV pressureduring first 1/3

rd of diastole rises rapidly during the period of early

diastolic filling. At the beginning of diastasis (this is the third phase of

diastole in which the RA and RV pressures are almost equal, and filling is

mainly the result of venous flow with the RA acting as a passive conduit.Also termed as the slow filling period) the resistance to filling

significantly increases, and the pressure then rises much more slowly untilthe onset of atrial systole (a

in Figure 3). This diastasis

period is much shorter with

rapid heart rates and the rapidfilling phase is followed

immediately by atrial

contraction.

Figure 3. Example of RV pressuretracing in a normal person. The a

wave represents atrial contraction.

iii. Pulmonary ArteryThe peak systolic pressure in the PA is equivalent to the peak

systolic pressure in the RV. Immediately after the end of ejection, the



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pulmonary valve closes and a dicrotic notch is seen on the pressure tracing

(Figure 4). Thereafter the pressure falls during diastole, to the level that isnearly equivalent to the mean LA pressure (or PCWP). Exceptions to the

equivalency of PA diastolic pressure and mean LA pressure are:

1) Rapid heart rate (the PA pressure does not have time to fall to the level

of LA pressure during diastole)2) Elevated pulmonary vascular resistance (PVR) with vasoconstriction

The mean PA pressure or diastolic PA pressure is elevated in

response to any condition that:1) Increases LA or PCWP (e.g. LV diastolic dysfunction, MS, MR)

2) Increases PVR at the arterial level

3) Selectively obliterates a significant portion of pulmonary vascular bedupstream to the arteriolar level (e.g. multiple or large thromboemboli)

Figure 4. Example of a PA

pressure tracing in a normal person. Note the variation in

peak systolic and diastolic

pressures with respiration.The dicrotic notch appears

shortly after the end of

ejection and the closure ofthe pulmonic valve.

iv. Pulmonary Capillary Wedge and Left Atrium

The PCWP (Figure 5) is an occluded pressure reflectingdownstream LA pressure provided that there is proper positioning,

and there are no intervening anatomic obstructions (e.g. pulmonary

venous obstruction, cor tritriatum). There is a time delay betweenthe PCWP and the LA tracings of about 140 to 200 msec. The

PCW and LA pressure tracings are again characterized by a, c, and

v waves. However when compared to the RA pressure tracing(Figure 2), the LA pressure pulse exhibits a normally dominant v

wave (<15 mmHg) and

a subordinate a wave

(<12 mmHg)

Figure 5. Example of PCWP

tracing, reflecting the LA pressure, in a normal person.



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b. Left Heart Catheterization

i. Left ventricleThe pressure pulse (Figure 6) is characterized by a peak systolic

pressure nearly equal to the peak aortic pressure (there may be a small

mid-systolic or late-systolic pressure gradient). In the absence of anyobstruction to LV outflow, this peak pressure occurs at the end of the first

1/3rd

of systole. The peak positive rate of rise of LV pressure (dP/dt )

occurs before the opening of the AV; the peak negative dP/dt occurssimultaneously with closure of the AV and marks the beginning of

isovolumetric relaxation in the LV. Following AV closure, the LV

pressure declines until decreasing pressure differential between LV andLA causes the opening of MV. At end-diastole, the pressure rises quickly

in response to atrial systole. The LVEDP immediately precedes the

beginning of isovolumetric contraction in the LV pressure pulse. Ingeneral, the mean PCWP, mean LAP, and LVEDP are all near equivalent

in magnitude.

The LVEDP is elevated (>12 mmHg) in:

1) LV diastolic volume overload (e.g. MR, AR, a large left-to-

right shunt)2) Concentric hypertrophy (decreased compliance) e.g. AS or

long-standing HTN

3) Decreased myocardial contractility (dilated LV)4) Restrictive or infiltrative cardiomyopathy

5) Constrictive pericardial disease (or a high pressure pericardial effusion)

6)

Ischemic heart disease. (Acute or chronic secondary to non-

compliance, scar)

ii. Ascending aorta

During ejection normal pressure in the ascending aorta parallelsLV pressure (Figure 6). Once the AV closes the aortic pressure declines

somewhat slower than the LV pressure. This reflects the accumulated

pressure waves from thoracic aorta and its tributaries as well as thecapacitance of the aorta. Following the dicrotic notch, there is a brief

increase in pressure due to some retrograde flow from the periphery into

the ascending aorta and the elastic recoil of ascending aorta. Then as the blood runs off into the periphery, there is a gradual decline in the systolic

arterial pressure until the next cardiac cycle.

The rate and magnitude of decline of aortic pressure duringdiastole are dependent on:

1) Aortic valve integrity (eg aortic insufiiciency)

2) Capacitance and resistance of the peripheral circuit



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3) Presence or absence of abnormal connection of aorta and the

pulmonary circulation or the right heart (e.g. PDA)4) Presence or the absence of a large arteriovenous fistula

Table 1. Hemodynamic values for normal adults

Figure 6. Normal Hemodynamics

c. Cardiac output (CO) determination

In the cardiac catheterization laboratory the cardiac output is usually

determined by one of two methods: (1) measurement of oxygen consumption,

and (2) indicator dilution technique. Each of these techniques will be reviewedfurther.

i. Measurement of Oxygen Consumption (Fick Method)Adolph Fick initially described this technique in 1870. The

principle used is that the uptake of a substance by any organ

system is the product of the arteriovenous concentration difference

of that substance and the blood flow to that organ. Hence if thelungs are used as the end organ, the pulmonary blood flow (whichis equal to the systemic blood flow in the absence of an

intracardiac shunt) can be determined by measuring the

arteriovenous difference in the oxygen across the lungs and theuptake of oxygen by the lungs.

The arteriovenous oxygen content difference (Ao – PA O2 content)

can be calculated (in ml oxygen) by the difference between the leftventricular oxygen content:

Measurement Mean value (mmHg)

SBP

DBP

MAP LVSP

LVEDP

LAP

PCWP PASP PADP

RVSP

RVEDP

RAP

130

70

85130

7

7

92410

24

4

4



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1.36 x Hemoglobin concentration x LV oxygen saturation

and the Mixed venous (pulmonary artery) oxygen content:

1.36 x hemoglobin concentration x PA oxygen saturation

The value 1.36 is derived from the fact that 1 gram of hemoglobin,

when 100% saturated, combines with 1.36 ml of oxygen.Therefore:

CO ( l/min ) = O2 consumption (ml/min)

Ao-PA O2 content (ml/l)

There are two techniques traditionally used for the

determination of oxygen consumption: (1) Douglas bag method,and (2) metabolic hood or the polarographic method. However it is

important to remember that no matter what method is used the patient needs to be breathing comfortably at a steady state. The

other source of error is the use of supplemental oxygen by the

patient during the procedure; this makes it difficult to calculate theoxygen content of inspired air. To minimize this error, it is

suggested that supplemental oxygen therapy be discontinued at

least 15 minutes prior to determination of cardiac output by theFick method. Alternatively VO2 can be estimated as 3 ml

O2/kg/min or 125 ml/min/m2.

1) In the Douglas bag method the patient is instructed to

breathe into a 60 liter sealed, airtight bag for a specific period of

time. The system is set up using a two-way valve with themouthpiece to allow the patient to breath in room air and the

exhaled air is directed and sealed into the bag. Once the specified

time is reached, the bag is removed from the patient and the

contents are analyzed. The room air needs to be analyzed as wellfor oxygen content.

VO2 (ml/min) = V E STP (F iO2-F E O2 ) x 10

Where VO2 is the oxygen consumption in ml/min, VESTP is the

expired volume of air corrected for standard temperature and pressure, FiO2 is the concentration of inspired oxygen (in room air

this is 20.93%), and FEO2 is the concentration of expired oxygen

(analyzed from the Douglas bag). The Correction for VE forstandard temperature and pressure is:

V E STP = V E ATP x 273 x P-W x P_

273+ T P 760



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Where VEATP is the measured expired volume at atmospherictemperature and pressure, T is room temperature in °C, P is the

barometric pressure in the room (mmHg), and W is the water vapor

pressure at the current room temperature (mmHg) (Table 2). At

20°C this value is 17.54 mmHg.

Table 2. Water Vapor Pressure (W) at various temperatures (°C) (From Sutton,

1998)

T (°C) W (mmHg)18 15.48

19 16.48

20 17.54

21 18.65

22 19.83

23 21.07

24 22.38

25 23.76

2) The metabolic hood (or polarographic method) utilizes a polarographic oxygen sensor cell to measure the oxygen content of

expired air. Room air is withdrawn at a constant rate from a plastic

hood that is placed over the patient’s head. The polarographmeasures the contents of the hood and the rate meter readout on the

unit provides the oxygen consumption in liters per minute. This

value is then used to calculate cardiac output.

ii. Indicator Dilution MethodThis method uses the mean concentration and transit time of an artificial

substance that is added to the blood stream. The most commonly usedmethod is cold saline (thermodilution) injected into the RA and theresulting temperature change is detected in the PA. Another indicator not

commonly used these days, is the indocyanin green dye. The dye is

injected into the central circulation (preferably PA) and is then detected in

a systemic artery.a. Indocyanin green dye

A precise quantity of green dye is mixed in a measured volume of

normal saline solution, and then precise known concentrations of 1mg/L, 5 mg/L and 10 mg/L are made. These solutions are then

used to calibrate the densitometer. Subsequently a measured

quantity of the green dye solution (typically 5 mg) is injected intothe blood stream (usually PA or SVC) and blood is continuously

withdrawn from the sampling site (usually aorta or any systemic

artery) using a pump. This blood is then sampled continuously

with the densitometer set to measure the concentration of the dyeaccording to the previous calibration. 20 to 30 seconds of data are

collected (Figure 7).



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The area under the curve is estimated (in mg.s/L). This value

along with the known amount of injected dye is used to calculatethe cardiac output by the following formula:

CO (L/min) = Amount of dye (mg) x 60 (sec/min) Area under the curve (mg.sec/L)

Figure 7. Indocyanin green dilution

curve. Are under this curve is used tocalculate CO (see text).

b. ThermodilutionRoom temperature (or iced) normal saline solution is injected into

the SVC or RA through the proximal port of the Swan-Ganz

catheter, the thermister which is located at the tip of the catheter isinserted in the PA. If room temperature saline is used there must

be at least 10 °C difference between the injectate and bodytemperature. A dilution curve is then constructed as cool saline

passes the thermister tip (Figure 8). The CO is then calculated by

the computer using the area under the curve as done for the dyeindicator technique (total of 3-5 outputs should be done). In a

number studies this method has shown good correlation with the

Fick method for calculation of cardiac output.

Figure 8. Thermodilutionmethod for measuring CO.

(From Otto, 1999)



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CO is calculated by the following formula:

CO (ml/sec) = Volume injected (ml) x Temperature difference ( ̊ C)

Area under the curve ( ̊ C.sec)

To get the CO in L/min the above value is multiplied by 0.06.

MR or AR does not directly influence the down slope of the

indicator-dilution curve. However, severe TR results in poormixing in the RA and subsequent loss of the indicator to the body

tissue before it reaches the PA.

d. Hemodynamic Equations

i. Cardiac Output

CO = SV x HR

CO = Oxygen consumption (ml/min) _______ AVO2 difference (mlO2 /L blood)

AVO2 is the difference between arterial and mixed venous

(pulmonary artery) O2 content

O2 content = saturation x 1.36 x hemoglobin concentration

ii. Cardiac Index (L/min.m2)

CI = CO (L/min)

BSA (m2 )

Normal 2.5-4.2 L/min.m2

iii. Stroke Volume (ml)

SV = CO (ml/min)

HR

iv. Stroke Index (ml/beat.m2)

SI = SV (ml/beat)

BSA (m2

)

v. Stroke Work

SW = (mean LV systolic P – mean LV diastolic P) x SV x 0.0144

vi. Pulmonary Artery Resistance (Wood units)



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PAR = mean PAP – mean LAP (or PCWP)

Q p

May use CO instead of Qp in absence of intracardiac

shunting. Multiply by 80 to get in metric units(dynes.sec.cm

-5) (i.e. PVRI). Normal range for PVRI is

225-315 dynes.sec.cm-5

Mean PAP = PAD + PAS – PAD

3

Normal range for mean PAP is 11-18 mmHg.

vii. Total Pulmonary Resistance (Wood units)

TPR = mean PAP

CO

Multiply by 80 to get in metric units (dynes.sec.cm

-5

) (i.e.TPRI)

viii. Systemic Vascular Resistance (Wood units)

SVR = mean systemic arterial P – mean RAP

CO

Multiply by 80 to get in metric units (dynes.sec.cm-5

) (i.e.

get SVRI). Normal range for SVRI is 1970-2390 dynes.sec.cm

-5.

Mean AP = DBP + SBP – DBP3

Normal range for MAP is 80-100 mmHg

C. Principles of Fluid Dynamics

Blood flow is a complex phenomenon. Time, space, location, and rheological

properties of the fluid within the vasculature are a few things that affect the

characteristics of blood flow. Normal intracardiac flow patterns are characterized

by laminar flow. This is the movement of fluid along well-defined parallelstreams with uniform flow velocities. In three dimension this flow consists of

concentric layers of flow, each with predictable direction and velocity (Figure 9).The outermost layer, which is in contact with the wall, is fixed in place by the

high degree of friction encountered at the interface. Adjacent, axially positionedlayers, however, slip past one another, with the velocity of motion of each layer

increasing from the tube wall to the central axis. Particles in each layer move

parallel to the vessel wall with no effective interaction occurring between the



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particles of individual layers. The slippage of fluid lamina over one another is

opposed by internal friction between fluid layers (viscosity).

Figure 9. Normal laminar flow can be represented as slippage of a series of thin concentric

cylindric shells over one another. The outermost shell is stationary, and the velocity increases to a

maximum at the central axis of the tube (From Weyman, 1994).

A fundamental property of all fluids is viscosity which opposes the slippage offluid lamina over one another. The amount of force required to overcome the

viscous resistance between layers is proportional to the area over which the layersare in contact and the velocity at which they are sliding past one another. The

stress (S) or force per unit area required to slide the layers over one another is

equal to the viscosity times the velocity gradient:

S = η dv/dx

Where dv/dx is the velocity gradient or the rate of shear across the tube, and η is

the viscosity. Viscosity therefore is equal to the ratio of stress to velocity gradientand is an inherent physical property of all fluid. This relationship implies that at

any given viscosity, the velocity gradient is a

function of the stress applied.

As mentioned earlier for laminar flow, the

particles in the flow stream move in a constant

direction, generally parallel to the vessel wall.This requires that sequential layers slip over one

another at an increasingly rapid rate as velocity

increases in the vessel. As the velocity reaches acritical threshold this orderly flow pattern begins

to breakdown and is replaced by an irregular,

seemingly random, particle motion known asturbulence. The progression from laminar to

turbulent flow follows a series of less well-

defined stages shown in figure 10.

Figure 10. Transition from laminar (A) to turbulent flow

(D).



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Osbourne Reynolds in 1833 described in detail factors that influence transitionfrom laminar to turbulent flow. These variables were combined in a

dimensionless term known as the Reynolds number ( N r ) which is described as

follows (for a cylinder):

N r = 2rv ρ / η

Where r is the radius of the tube, v is the mean velocity of the flow, ρ is the

density of blood, and η is the viscosity. This number represents the ratio of inertial

to viscous forces. The higher theReynolds number, the greater the

tendency towards turbulence.

The critical threshold betweenlaminar and turbulent flow is

roughly 2300.

Figure 11. Parabolic flow pattern that

normally occurs during steady flow in a

rigid cylindric tube (From Weyman,

1994).

The speed at which individual lamina move and the pattern or profile assumed bythe blood column in different circumstances are the net result of the balance of the

inertial forces promoting forward motion and the viscous forces retarding thatmotion. For steady flow in a rigid tube the flow is parabolic (Figure 11). Such

parabolic profile assumes a velocity gradient that changes linearly across the tube

and is the most energy efficient form of fluid flow.

D. Role of Echocardiography in Assessment of Cardiac Hemodynamics

Since the first attempt to use ultrasound as a medical diagnostic tool in 1942 by

Dusik, the technology has undergone dramatic change. With the advent of highfrequency transducers, Doppler imaging, and tissue harmonic imaging (just to

mention a few), echocardiography has become an invaluable tool for assessmentof patients with cardiac disease. Doppler echocardiography has for the most partreplaced cardiac catheterization for assessment of cardiac hemodynamics.

However there are still a number of hemodynamic parameters that can only be

determined at cardiac catheterization (eg PVR) The obvious noninvasive nature

of echocardiography makes it an attractive tool for assessment of cardiachemodynamics. Data that can be obtained by echocardiography are listed below:



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Table 2. Hemodynamic data obtained by echocardiography

Pressure gradients

Maximal instantaneous and mean gradientsVolumetric measurements

SV and CO

Regurgitant volume and fractionQ p/Qs ratio

Valve area

Stenotic and regurgitant orifice areasIntracardiac pressures

PAP, LAP, and LVEDP

Measurements of systolic function

EF, LV mass, wall stress, Vcf

Measurements of diastolic functionE/A ratio, IVRT, DT, dP/dt, τ Color M-mode, TDI, Vp

a.

Valvular Stenosis

The fluid dynamics of a stenotic valve are characterized by a

laminar high velocity jet across a narrowed orifice. Figure 12 shows thisrelationship between flow and cross-sectional area. The flow is directed in

such a way that the narrowest cross-sectional area of flow (physiological

orifice area) is smaller than the anatomic orifice area.

Figure 12. Illustration of fluid dynamics ofthe stenotic AV in systole. As LVOT flow

accelerates and converges, a relatively flat

velocity profile occurs proximal to thestenotic valve. In the stenotic orifice, a high

velocity laminar jet is formed with thenarrowest flowstream occurring downstream

from the orifice. Beyond the jet, flow is

disturbed, with blood cells moving inmultiple directions and velocities. (From

Otto, 2000)

The pressure gradient across

a stenotic valve is related to the velocity in the jet, according to the

Bernoulli equation:

∆ P = ½ ρ (v22-v1

2 ) + ρ (dv/dt)dx + R(v)

Corrective Local Viscousacceleration acceleration resistence

Where ∆ P is the pressure gradient across the stenotic valve, ρ is

the mass density of blood (1.06 x 103 kg/m

3), v2 is velocity in the stenotic

jet, v1 is the velocity proximal to the stenosis, (dv/dt)dx is the time-varying



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velocity at each distance along the flow stream, and R is the constant

describing the viscous losses for that fluid and orifice. This equation wasfirst proposed by Daniel Bernoulli who in 1738, documented that faster

moving fluids exert less force on surfaces they are flowing along from the

studies of steady water flow in rigid tubes.. Little did he know that this

discovery would eventually change the way we travel and the way somesports are played. Subsequently this equation was applied to Doppler data

to stenotic valves in the late 1970s.

If we eliminate the terms for viscous losses and acceleration, andsubstitute the known values for density of blood the Bernoulli equation

can be reduced to:

∆ P = 4(v22-v1

2 )

The proximal velocity is commonly less than 1m/s for stenoticvalves and is even smaller when squared and hence can be ignored to give

the Simplified Bernoulli equation:

∆ P = 4v2

Highly accurate and reproducible calculations of maximal pressure

gradients and mean pressure gradients can be obtained using the above

equation. It should be noted that velocity profiles are influenced by the

amount of flow, so high output states may exaggerate v2.

b. Cardiac output determination by echocardiography

Calculating the cardiac output by echocardiography uses the same principle as the

cardiac catheterization methods.

CO = SV x HR

The stroke volume (SV) can be calculated from the cross-sectional area of the

outflow tract (in cm2) and the velocity-time integral (VTI) (in cm). The LVOT is

the location used most frequently to determine SV. Both the LVOT and theRVOT can be used to calculate CO. When LVOT is used, VTI of flow across

LVOT is used using PW Doppler. For RVOT measurements, parasternal short-

axis view at the level of RVOT is used to measure the diameter and the flow

across RVOT by PW Doppler.

SV = π D2 x VTI

4Where D is the diameter of the LVOT (in cm). Substituting for SV we get

CO (ml/min) = (0.785 x D2 x VTI) x HR (beats/min)

Note that CO determined by this method is in ml/min, to get CO in L/min divide

the above value by 1000.



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Indices of Left Ventricular Systolic Function

A. Cardiac catheterization

Cardiac catheterization has been used to assess the LV systolic and

diastolic function

a.

Assessment of LV volume and LVEFGeometric methods for estimation of LV volumes assume that the LV

shape is a prolate spheroid. Although this is not exactly the case, it can beused to calculate LV volume and EF. The 30° RAO projection is used.

Assuming an ellipsoid, volume is calculated as:

V = 4π x D x D x L = π x D2 x L

3 2 2 2 6

Where D is the length of the minor axis and L is the length of the major

axis. This equation is uncorrected for magnification; the magnificationfactor (f) is calculated from filming a marked catheter of known length.Hence the corrected volume equation becomes:

V = π x D2 x L x f

3 = 0.524 x D

2 x L x f

3

6The above formula can be simplified by measurement of area (A) in cm

2

and the major axis length (L) in cm and their relationship to the minor axis

length by the following formula:

D = 2A

2 π LSubstituting for D in the previous formula we get:

V = 0.849 x A2 x f

3

L

For measurements of EF, f 3 cancels out and one can use the following

formula for calculation of volumes:

V = 0.85 x A2

L

The LV volumes are then measured in end systole (ESV) and end diastole(EDV), ejection fraction is then calculated by:

EF = EDV – ESV x 100

EDV



20

Figure 13. LV end-diastolic and end-systolic images (RAO) used for calculation of

LVEF (From Peterson, 1997). (1= anterobasal, 2= anterolateral, 3= apical, 4=

diaphragmatic, 5= posterobasal)

b. Measurement of LV mass

The LV mass is calculated from the difference between the LV cavity

volume and the volume of LV cavity and the LV wall. It is assumed thathe LV has a uniform wall thickness. If W is taken as the wall thickness at

the intersection point of the minor axis (D) and major axis (L) (assuming

an ellipsoid shape) (Figure 14), and

the specific gravity of heart muscle is 1.05 (gm/ml), then the LV mass isgiven by:

LV mass = 1.05 x LV myocardial volume

LV mass = 1.05 x (V C+M – V C )

Where VC+M is the volume of LV cavity and myocardium, and VC is the

ventricular cavity volume. Substituting for the volumes and using f as themagnification factor, we get:

LV mass = 1.05 x [4π f 3 (D + W)

2(L + W)] – [ π f 3

D2 L]

3 2 2 LV wall and cavity cavity

volume volume

Figure 14. Estimation of LV volume by single-plane 30° RAO

projection. L, major axis; D, minor axis in two planes; and W,

wall thickness. All measurements are in cm.

12

3

45



21

This technique has been validated by comparison with volume

displacement measures of postmortem hearts and is surprisingly accuratedespite the aforementioned assumptions and the inherent errors associated

with multiple measurements in two dimensions.

B.

Echocardiographya. LV mass

A similar principle is used in calculating LV mass using echocardiography

technique. Hence one can trace the epicardial borders to calculate the totalvolume of the ventricle, and subtracting the volume determined by

endocardial border tracing. This value is then multiplied by the specific

density of myocardium, 1.05 gm/ml. However, epicardial definition israrely adequate for this approach. Instead mean wall thickness is

calculated from epicardial (A1) and endocardial (A2) cross-sectional areas

in short-axis view at the papillary muscle level (Figure 14). The short axisradius b is calculated as:

π /2 Ab =

Mean wall thickness t , is then calculated as:

b At −= π /1

and the cross-sectional area of the myocardium ( Am) in short axis view is:

Am = A1 – A2

Figure 15. Diagram of the LV short axis at thelevel of papillary muscle tip demonstrating

epicardial and endocardial parameters used tocalculate myocardial thickness (t), short axis

radius (b), and areas (A1 and A2). Note that the

papillary muscles are excluded when measuring

these parameters (From Oh, 1999).

Myocardial mass is then calculated from

the above measurements plus the LV

length ( L) from the level of the short

axis plane to the base (d ) and to the apex (a) (measured from the apicalapproach) such that d + a = L (Figure 15). Using the truncated ellipsoid

formula,

LV mass = 1.05π {(b + t)2[ ⅔(a + t) + d – d 3 /3(a + t)2 ] – b2 [ ⅔a + d – d 3 /3a2 ]}

or if one uses the area-length formula, as:

LV mass = 1.05{[5/6A1(a + d + t)] – [5/2A2(a + d)]}



22

Images needed for calculation of LV mass are shown in

Figure 16. A number of important assumptions are made

using the above method. One is that the parasternal

short-axis view is assumed to be circular and its area isused to calculate the radius in short axis and wall

thickness. The other assumption is that the LV is

ellipsoid in shape.

Figure 16. Parasternal short-axis view at the papillary muscle level.Epicardial and endocardial borders are traced at end-diastole (A) for

calculation of LV mass, in combination of LV length (L)

measurement from an apical approach. The end-systolic short-axisimage (B) is not used for calculation of ventricular mass (From Otto,

2000)

A simpler method which does not require measuring LV

length in the long-axis view is as follows:

LV mass (g) = 1.05[(LVID + PWT + IVST)3 – LVID3 ] x 0.8 + 0.6

Where LVID is left ventricular internal dimension, PWT is posterior wallthickness, IVST is the interventricular wall thickness (all measured in

diastole), 1.05 is the specific gravity of the myocardium in g/ml, and 0.8 is

the correction factor. All measurements are taken in the short-axis view atthe papillary muscle level. Normal ranges are (mean values) 148 ± 21 g or

99 ± 15 g/m2 for men, and 108 ± 21 g or 78 ± 15 g/m2 for women. The

95% confidence limit for the upper range of normal is 131 g/m2 for men

and 100 g/m2 for women.

b. Fractional Shortening

Fractional shortening (FS) of the LV is calculated from either M-mode or

two-dimensional linear measurements. It can be calculated by thefollowing formula:

FS = LVEDD – LVESD x 100 LVEDD

Where LVEDD is left ventricular end-diastolic diameter and LVESD is

the left ventricular end-systolic diameter. These are measured from the



23

M-mode tracings (Figure 17). Normal range

is 25-42% (95% confidence limits). With

nonsymmetrical disease (ischemic disease) or

with alterations in LV shape (dilated CM ), FS

will not represent the overall LV function. In

the absence of wall motion abnormalities,there is a relatively good correlation between

FS and ejection fraction (EF).

Another important issue is the way thedistances are measured during M-mode

echocardiography. The American Society of

Echocardiography (ASE) has recommendedleading-edge-to-leading-edge M-mode

measurements. Leading-edge is the edge of the echo closest to the transducer,and the edge away from the transducer is the trailing edge. Another conventionis the measurement of M-mode distances using the trailing-edge-to-leading-edge

method. Although this method is attractive because it corresponds to visual space

between two objects it is highly variable. This variability is secondary to

instrument differences, and gain settings.

c. Left ventricular volume and ejection fraction

Usually end-diastolic (EDV) and end-systolic volumes (ESV) aremeasured for assessment of LVEF according to the formula:

EF (%) = SV_ X 100 EDV

SV = EDV – ESV

i. Modified Simpson’s (Apical Biplane method)One can imagine the left ventricle as a series of discs of equal height

(Figures 18 and 19). LV volume is the sum of the volumes of the

discs. The volume of each disc can be calculated from its thickness

and area. Recordings from the apical two and four-chambered viewsare used to calculate the volumes of discs in two views. The LV

volume is then calculated as the sum of the volumes of the discs as:

∑=

=20

1

4/i

iibaV π x (L/20)

Where V is the LV volume, ai and bi are the disc diameters in the

apical two- and four-chambered views respectively, and L is thelongest length of the left ventricle which is divided into 20 discs.



24

This method is highly dependent on the operator’s ability to identify

endocardial borders. This is a major source of error for this method.

Figure 18. Determination of LV

volume by modified Simpson’s

rule. Apical two chamber andfour chamber views are used. ai

and bi are disc diameters in

apical two chamber and four

chamber views respectively.

Figure 19. Use of biplane modified Simpson’s rule to calculate EF (From ECHO SAP III, ACC)

ii. Single plane area-length method

When only one apical plane is available for measurement thismethod is used for measurement of LV volume (Figure 20). Thesingle plane area-length method uses the length, L and the two-

dimensional area, A of a single long-axis view. The LV volume is

calculated assuming an ellipsoid shape of the LV as:

V = 8A2

3π L



25

This formula can be written as:

V = 0.85 x A2

L

Figure 20. Determination of the LV volume by the single plane area length method. L,

length of LV; A, area of LV

iii. Quinones method

Quinones and colleagues proposed a simplified method fordetermining EF using both M-mode and 2D imaging.EF is determined by the following formula:

EF = (% ∆ D2 ) + ([1 - ∆ D2

] x [% ∆ L])

Where % ∆ D2 = LVEDD

2 – LVESD

2 x 100%

LVEDD2

∆ D2 = LVEDD

2 – LVESD

2

LVEDD2

% ∆ D2 = the fractional shortening of the square of the minor axis,

and% ∆ L = the fractional shortening of the long axis, mainly related to

apical contraction:

Normal 15%

Hypokinetic apex 5%

Akinetic apex 0%

Dyskinetic apex -5%Apical aneurysm -15%

This method provided good correlation when compared with radionuclideand cineangiographic methods (r = 0.89 to 0.93)

d. Velocity of circumferential fiber shortening (Vcf)

This measure may be a more meaningful estimate of LV function than EF

because it reflects not only the normalized amplitude but also the rate of

fiber shortening. The Vcf , expressed in circumferences per second, is



26

normally calculated by assuming that the LVID reliably represents the

circumferences of the LV at the base. It is expressed as:

Vcf = LVIDd – LVID s LVIDd x ET

Vcf = FS ET

Where ET is the ejection time derived either from the carotid pulse

tracing, the duration of aortic valve opening, or from the onset of peak of

posterior LV wall movement. LVIDs and LVIDd are internal dimensionsof LV in end-systole and end-diastole respectively, and FS is the fractional

shortening. The lower limit of normal for Vcf is 1.1 circumferences per

second.

e. The rate of change of LV pressure (dP/dt)

Noninvasive evaluation of dP/dt is possible by Doppler measurements in

patients with mitral regurgitation. Continuous wave Doppler (CW) is usedto record the complete velocity profile of regurgitant

flow across the mitral valve. Using the simplified

Bernoulli equation, the velocity curve can beconverted to a pressure gradient curve (∆P), the

derivative of which gives instantaneous d ∆ P/dt (Figure 21 and 22). Measurements of dP/dt done

using the CW Doppler closely match the values

determined by cardiac catheterization.

Figure 21. Graph showing Doppler derived LV pressure

gradients (CW Doppler) and dP/dt curve (bottom) determined by

Doppler mitral regurgitant velocity spectrum (CW Doppler).

The usual method for calculation of dP/dt is to measure the time for theMR velocity to rise from 1 to 3 m/s. Assuming a constant LA pressure,

the LV pressure will have increased from 4 to 36 mmHg (simplified

Bernoulli). Then the rate of pressure change (dP/dt ) is calculated asfollows:



27

dp/dt = 32 mmHg

Time interval (sec)

Typically this is greater than 1200 mmHg/s. However

with poor LV functions values less than 1000 mmHg/sare obtained.

Of course measurements of dP/dt can only be made in presence of mitral regurgitation and it assumes a

parallel intercept angle between the MR jet and the

ultrasound beam throughout the cardiac cycle.

Normal value of –dP/dt calculated fromechocardiographic studies is 2048 ± 335 mmHg/s.

Figure 22. CW Doppler mitral regurgitant

curves in normal (A) and severely reduced

(B) LV systolic function (from Otto, 2000).

f. LV wall stress ( σ )

The common measurements of LV systolic function such as EF, FS, Vcf

and to some extent dP/dt , do not differentiate between abnormalities of

myocardial contractility and alterations in afterload and preload. Hence ameasure of the force-length relationship is required to truly characterize

myocardial contractility. The use of wall stress as a measure of

myocardial function is based on the principle that, for equilibriumto exist at any time during the cardiac cycle, the forces acting

within the ventricular wall must exactly balance the forces actingon it. LV wall stress is a function of thickness of the ventricular

wall, chamber size and configuration, and interventricular pressure.

Figure 23 demonstrates the circumferential, meridional, and radialstresses acting on the ventricular wall.

Figure 23. Circumferential (σc), meridional (σm), and radial (σr ) components of

LV wall stress are mutually perpendicular (From Weyman, 1994).

Meridional wall stress (σ m) can be calculated from the LV peak pressure P ,

the myocardial area Am, and the LV cavity area Ac in the short-axis view atthe papillary muscle level done at end-systole (see Figure 14).

σ m = 1.33P(Ac /Am ) x 103 dyn/cm

2

Meridional wall stress (σ m) can be calculated from LV peak pressure (P),

myocardial area (Am), and the LV cavity area (Ac):



28

σ m=1.33P(Ac /Am )x103 dynes/cm

2 (from 2D) OR

σ m= PxLVID (from M-mode measurements)

4h(1+h/LVID)

Where h is wall thickness and LVID is the left ventricular internaldimension

Non-invasive measure of σ m in end systole (es) can be done using the

following formula using systolic blood pressure (SBP):

σ m(es)=0.334(SBP)(LVIDs)

h(1+h/LVIDs)

Normal values for meridional wall stress have been reported between 65

to 73 x 103 dynes/cm

2.

Circumferential wall stress σ c can be calculated using the same variables plus the ventricular length L measured from the apical four-chamberedview as:

σ c = [(1.33P √ Ac )/( √(Am +Ac ) - √ Ac )] x [1- (4Ac√ Ac / π L2 )/( √(Am +Ac ) - √ Ac ) kdynes/cm2

Normal end-systolic circumferential wall stress has been reported as 213 ±

29 dynes/cm2.

Diastolic Function and DysfunctionA. Introduction

Some patients with heart failure and normal LV systolic function have predominantly diastolic dysfunction. More patients have a combination of

systolic and diastolic dysfunction. In these patients the LV is not dilatedand may contract normally, but the ventricular diastolic function is greatly

impaired. In this form of heart failure, the LV has reduced compliance

and is unable to fill adequately at normal diastolic pressures. This

condition results in reduced end-diastolic volumes, an elevated end-diastolic pressure, or both. Reduced LV filling volume leads to decreased

stroke volume and symptoms of low output, whereas increased filling

pressures lead to symptoms of pulmonary congestion.Several studies have shown that as many as 40% of all patients evaluated

for clinical diagnosis of heart failure have preserved LV systolic function.Several factors predispose to increased diastolic “stiffness” in a LV withnormal systolic performance. These include myocardial ischemia,

myocardial fibrosis, LVH, and LV pressure overload. One condition in

which many of these factors coexist is systemic hypertension. Due to high prevalence of HTN routine assessment of diastolic function in patients

presenting with symptoms of heart failure is important.



29

B. Assessment of LV diastolic function with Cardiac Catheterization

Classic definition of diastole starts with the opening of the mitral valveand ends with the onset of systolic contraction when the mitral valve

closes. The clinical definition of diastole includes isovolumetric

relaxation as well; hence, diastole really starts at the end of ejection when

aortic valve closes. The closure of AV often precedes the peak negativedP/dt (rate of fall of LV pressure). The onset and the rate of relaxation are

governed by a variety of factors including load, inactivation andsynchronicity.

a. Time constant of ventricular relaxation ( τ )

Several indices have been used to quantitate relaxation, such as peak

negative dP/dt , and time constant for isovolumetric pressure decay (τ inmsec). The time constant can be calculated based on the relationship

between instantaneous negative dP/dt and the LV pressure during the

phase of isovolumetric relaxation.

Figure 24. Determination of time constant (T)of the LV pressure decay from the linear

relationship between the LV pressure and

-dP/dt during isovolumetric relaxation, whichis defined as the time interval between peak

–dP/dt and MV opening. The time constant

(T) is 43 ms and the intercept (P b) is -6 mmHg

in this normal patient. Slope of this curve is α (from Peterson, 1997).

The equation used to describe LV pressure decay during isovolumetric

relaxation is:

P = Ae-αt

+ P b

Where P is the LV pressure (mmHg), A is LV pressure at peak –dP/dt (mmHg), e is the base of natural logarithm, α is the slope of pressure-time

relationship (sec-1

), t is time (sec), and P b is the pressure asymptote(mmHg). The time constant (τ) has been defined by investigators as:

τ = -1/ α

Assuming a linear relationship between –dP/dt and LV pressure during

isovolumetric relaxation:

dP/dt = α (P – P b )



30

substituting for α

dP/dt = -1/ τ (P – P b )Therefore:

τ = -(P – P b )dP/dt

The normal value for the time constant ( τ ) of relaxation using the above

method is 41 ± 12 msec.

b. Diastolic filling rate (DFR)

Another measure of diastolic function is the diastolic filling rate (FR).

This value can be obtained angiographically from frame-by-frameanalyses at 20 msec intervals. Diastolic FR is calculated as:

FR = V(t + 0.02) – V (t – 0.02)

0.04

FR is the filling rate (ml/s), V is the LV volume (ml), and t is time (sec).

The greatest values occurring in the first and second halves of diastole are

termed early and late peaking filling rates, respectively (Figure 25).

The diastolic filling time interval from the beginning of diastolic filling toend-diastole can be divided into a first and second half, and the ratio of the

volume increase during the first (%V1) and second (%V2) halves of

diastole can be used as a measure of early and latediastolic filling. Normal values for peak filling rate

have been determined. These are 483 ± 111 ml/s during early diastole (PFR

1) and 321 ± 102 ml/s

during late diastole (PFR 2); %V1 amounted to 65%

and %V2 to 35%.

Figure 25. LV diastolic filling in a normal patient. LV

volumes (upper) were determined angiographically every 20

msec. Instantaneous LV filling rates (lower) and peak filling

rates during early diastole (PFR1) and during atrial contraction(PFR2) are shown. The volume increase from MV opening to

end-diastole (ED) are shown and divided into a first (t1) and

second (t2) halves. Percent volume increase during the first

(%V1) and second (%V2) halves of diastole are used as a

measure of early and late diastolic filling. ES, end-systole.(From Peterson, 1997)



31

C. Echocardiographic assessment of LV diastolic function

a. Doppler echocardiography

Doppler recordings of LV diastolic filling velocities closely correspond to

ventricular filling measurements done using other techniques. The normalLV Doppler inflow pattern (Figure 26) shows an interval between aortic

valve closure and mitral valve opening (IVRT). Immediately following

MV opening there is a rapid acceleration of blood from the LA to the LVwith an early peak velocity (E velocity) of 0.6 to 0.8 m/s occurring

approximately 90 to 110 ms after MV opening in healthy, young

individuals. After this, flow decelerates rapidly, with a normaldeceleration slope of 4.3 to 6.7 m/s

2. This is then followed by a period of

minimal blood flow (diastasis). Atrial contraction causes the LA pressure

to elevate above the LV pressure, resulting in a second velocity peak (Avelocity) which typically ranges from 0.19 to 0.35 m/s in healthy, young

individuals.

Figure 26. Quantitative measurements from the

Doppler curve of LV inflow.

Mitral inflow velocities are recorded using

PW Doppler from the apical four or two-

chamber views. This allows a parallel

alignment of ultrasound beam and thedirection of the blood flow. Table 4 shows

some of the normal parameters of diastolic

calculated using Doppler derivedmeasurements.

Table 4. Normal parameters of Diastolic Function (From Oh, 1999) Parameter Age 2-20 Age 21-40 Age 41-60 Age >61

IVRT 50 ± 9 ms 67 ± 8 74 ± 7 87 ± 7

E velocity 88 ± 14 cm/s 75 ± 13 71 ± 13 71 ± 11

A velocity 49 ± 12 cm/s 51 ± 11 57 ± 13 75 ± 12

A duration 113 ± 17 msec 127 ± 13 133 ± 13 138 ± 19 E/A ratio 1.88 ± 0.45 1.53 ± 0.4 1.28 ± 0.25 0.96 ± 0.18

Deceleration Time 142 ± 19 msec 166 ± 14 181 ± 19 200 ± 29

PVa velocity 16 ± 10 cm/s 21 ± 8 23 ± 3 25 ± 9

PVa duration 66 ± 39 msec 96 ± 33 112 ± 15 113 ± 30

PVs velocity 48 ± 10 cm/s 44 ± 10 49 ± 8 52 ± 11

PVd velocity 60 ± 10 cm/s 47 ± 11 41 ± 8 39 ± 11

PVs/PVd 0.82 ± 0.18 0.98 ± 0.32 1.21 ± 0.2 1.39 ± 0.47



32

Impaired LV relaxation results in the classic pattern of diastolic dysfunction

with impaired early diastolic filling and an increased contribution of theatrium to total LV filling. This results in a reduced E velocity, a longer IVRT,

a prolonged early diastolic deceleration time, and an E/A ratio of <1 (Figure

27). Abnormal ventricular compliance (restrictive pattern) results in a rapid

early diastolic filling with a shortIVRT. The atrial contribution to

filling is small due to an elevated

LVEDP (small pressure difference between LA and LV).

Figure 27. LV and LA pressure tracings

and the corresponding mitral inflow

velocities in three different diastolic

filling patterns (From Oh, 1999).

As diastolic function deteriorates, a transition from impaired relaxation to

restrictive filling occurs. During this transition, mitral inflow pattern goesthrough a phase resembling a normal pattern, with an E/A ratio of 1 to 1.5 and

a normal deceleration time (160 to 200 ms). This occurs because of a

moderately increased LA pressure superimpose on the relaxation abnormality.This is referred to as a pseudonormalized pattern, and represents moderate

diastolic dysfunction. This abnormality can be unmasked using the Valsalva

maneuver (Figure 28). The E/A ratio decreases to <1.0. In normal subjects

both the E and A velocities decrease proportionally keeping the same E/Aratio.

Figure 28. PW Doppler mitral inflowvelocities recorded during the

different phases of the Valsalva

maneuver. During Valsalvamaneuver, the reduction in preload

unmasks the underlying impaired

relaxation of the LV (End), with a

decrease in E velocity and an increase

in A velocity.

An indirect approach to evaluation of diastolic function is the measurements ofatrial filling patterns and pressures (Figure 29). RA filling is characterized by a

small reversal of flow following atrial contraction (a wave), a systolic phase, asmall reversal of flow at end-systole (v wave), and a diastolic filling phase.

Doppler evaluation of hepatic vein flow can be used to assess RA filling. For LA

filling the pulmonary vein (PV) Doppler flow is assessed. The PV Doppler flowis characterized by a small reversal of flow following atrial contraction (a wave),



33

a systolic filling phase, a blunting of flow or

brief reversal at end-systole, and a diastolicfilling phase.

Figure 29. Schematic representations of RA (hepaticvein) and LA (pulmonary vein) filling patterns and the

close correspondence with the pattern of jugular

venous pulsations. (From Otto, 2000)

There are four distinct velocity components in PV Doppler recordings (Figure

30). There are two systolic velocities (PVs1 and PVs2), diastolic velocity (PVd),

and atrial flow reversal (PVa). PVs1 occurs earlyin systole and is due to atrial relaxation (decreasing

LA pressures). PVs2 occurs in midsystole and is

produced by an increase in pulmonary venous pressure. Both peak velocity (PVa) and duration of

pulmonary vein atrial flow (PVa dur) increase with

higher LVEDP, and are complementary

measurements for assessment of LV diastolicfunction.

Figure 30. PW Doppler recording of PV demonstrating its

four velocity components. Atrial flow reversal (PVa), two

systolic velocities (PVs1, and PVs2) and diastolic velocity

(PVd). (From Oh, 1999)

Table 5. Classification of diastolic filling based on Doppler findings

Table 5 shows the classification of diastolic filling patterns based on the

different measurements made by Doppler echocardiography.

Normal Impaired

relaxation

Pseudonormalization Restriction

DT 160-240 msec >240 160-200 <160

IVRT 70-90 msec >90 <90 <70

E/A ratio 1.0-2.0 <1.0 1.0-1.5 >1.5

PVs2 /PVd ratio ≥1.0 PVs2>>PVd <1.0 PVs2<<PVd

Adur/PVa dur ≥1.0 ≥1.0 or <1.0

depending onLVEDP

<1.0 <1.0

Response to preload

reduction (e.g.

Valsalva)

Reversal of E/A ratio (to

<1.0)

Decreased E/A

ratio



34

b. Index of myocardial performance

Another measure of both diastolic and systolic function is the index ofmyocardial performance (IMP). Systolic dysfunction causes prolongation of

isovolumetric contraction time (ICT) as well as shortening of ejection time

(ET). Both systolic and diastolic dysfunction result in abnormal myocardial

relaxation, leading to prolonged isovolumetric relaxation time (IRT). IMP isexpressed as:

IMP = ICT + IRT

ET

The time intervals needed to calculate IMP are obtained by Dopplerechocardiography are shown in Figure 31. The normal value for IMP is 0.39

± 0.05.

Figure 31. Diagram illustratingmeasurements required for the calculation of

index of myocardial performance (IMP).

(From Oh, 1999)

c. Time constant of ventricular relaxation ( τ )

Another measure of diastolic function is the time constant for ventricularrelaxation (τ). This value measured by Doppler is an adaptation from cardiac

catheterization methods. In this technique the down-slope of the regurgitant

AV valve Doppler velocity waveform is translated into pressure-timewaveform using the simplified Bernoulli equation. The resultant curve is then

numerically fit into the following exponential equation:

P(t) = P oe-t/ τ where P o = 4v peak

2

Since numerical curve fitting is not practical a simpler method is used to

determine the time constant of ventricular relaxation using IVRT, peaksystolic BP (Ps), and LA pressure (PLA): (ln is the natural logarithm)

τ = IVRT_______ln(P s ) – ln (P LA )

LV outflow

Mitral Inflow

IRTICT

a

b

ET

Index = ICT + IRT = a - b

ET b



35

The time constant of relaxation is relatively independent of preload but is

altered by afterload. A limitation of the use of this value is that theisovolumetric LV pressure decay is not always a perfectly simple exponential

decay function. Actual LV pressure tends to fall faster during the latter part of

isovolumetric relaxation than the one predicted from the monoexponential

decay. Normal value for τ derived from echocardiographic studies is 33 ± 6ms.

d. Tissue Doppler imaging (TDI)

Recently developed technique of tissue Doppler imaging (TDI) has been applied

to measurements of diastolic function and dysfunction. Instead of blood flow,

TDI measures the velocity of the myocardium during the cardiac cycle. Bloodflow is typically low amplitude and high velocity in nature, whereas myocardial

velocities are of high amplitude and low velocity. TDI velocities can be displayed

three ways, either as spectral PW signal (Figure 32), as a color velocity encodedM-mode, or as a 2D color map.

Figure 32. Characteristic

mitral annular motion

spectra compared to

normal and abnormal PWmitral inflow velocity

patterns. Sample volume

is placed either at theseptal wall or the lateral

wall at the mitral annulus.

Imaging from an apical window is performed, because from this view theaxial motion of the LV is parallel to the transducer axis and the velocities are

primarily related to the LV contraction and relaxation. A 3-7 mm PW sample

volume is placed in different segments of LV (e.g. septum, anterior, inferiorwalls) and regional quantification of segmental velocities are obtained. For

the purpose of recognition of pseudonormal mitral velocity patterns, the PWsample volume is usually placed within the septal or the lateral regions ofmitral annulus (Figure 33).



36

Figure 33. Scan-line orientation for

longitudinal axial TDI of septal (left)and lateral (right) mitral annular

velocities (From Appelton et al.,

2000).

Mitral annular velocities

are usually less than 20 cm/s.The velocity pattern of mitral

annulus is similar to those of

mitral inflow. There is a positive (towards apex) systolic

signal (Sm) and negative signals

in early (E′ ) and late (A

′ )

diastole for patients in normal sinus rhythm. In normal ventricular diastolic

function the peak of the E′ wave occurs earlier than the E wave in mitral

inflow velocity. Similar to mitral inflow velocity profiles, in patients withimpaired relaxation, there often is an E

′ /A

′ ratio of <1.0.

Table 6. Mitral annular velocities in normal volunteers (from Sohn et al., 1997)20-29 yrs 30-39 yrs 40-49 yrs 50-59 yrs 60-69 yrs Total

Peak E ′ velocity 11.8 ± 1.4 13.0 ± 1.9 9.2 ± 1.4 8.5 ± 1.9 7.5 ± 1.6 10.0 ± 1.3

Peak A′ velocity 8.6 ± 1.6 8.7 ± 1.8 9.2 ± 1.4 10.2 ± 1.5 10.7 ± 2.2 9.5 ± 1.5

E ′ /A′ ratio 1.4 ± 0.2 1.5 ± 0.5 1.0 ± 0.2 0.8 ± 0.2 0.7 ± 0.1 1.1 ± 0.2

e. Color M-mode echocardiography (CMM)

Color M-mode recordings (CMM) provide the spatial and temporal

velocity characteristics of flow along an entire echocardiographic scan line.

The obvious advantage of this modality is that it allows measurement of flowvelocities in many points along the heart with superior temporal, spatial, and

velocity resolutions. To obtain CMM recordings, the color Doppler function

is activated while imaging from the apical four-chamber window. The colorsector is placed to include the LV, MV, and about half of the LA. Aliasing

velocity is set to 55-60 cm/s, then M-mode cursor is aligned with mitral

inflow (from LV apex through the MV and into the LA) and a sweep rate of

100-200 mm/s is set. Similar to PW recordings patients in sinus rhythmdisplay two distinct waves (corresponding to E and A waves) in diastole. The

most commonly used variable of CMM is the propagation velocity of early

diastolic flow (E wave) into the LV (Vp). There is a significant negative

correlation between Vp and the time constant of LV relaxation (τ). Figures 34and 35 represent different profiles (and hence Vp) in diastolic dysfunction. It

must be noted that TDI and CMM currently are mainly investigational butshow great deal of promise and will soon be part of routine echocardiographic

evaluation of patients with diastolic dysfunction.



37

Figure 34. Transthoracic color M-mode image from patient with normal diastolic function.The slope of early diastolic (E wave) flow propagation (Vp) is identified (dashed line). A

steeper line is associated with faster relaxation and greater diastolic suction whereas a

shallower slope (Figure 32) is associated with impaired relaxation.

Figure 35. Transthoracic CMM image from a patient with severe diastolic dysfunction

secondary to dilated cardiomyopathy. Compare the slope of the early diastolic flow

propagation (Vp) in this patient with one from a patient with normal diastolic function in

figure 31.

Vp

Vp



38

Finally figure 36 summarizes the findings of Doppler and M-modeassessment in diastolic dysfunction.

Figure 36. Representative Mitral inflow, pulmonary venous flow (PV flow), tissue

Doppler echo (TDE), and color M-mode (CMM showing slope of early diastolic

propagation, Vp) patterns in patients with normal and abnormal diastolic function(modified from ECH SAP III Vol 1, ACC).

Table 7. TDI and CMM derived values suggestive of impaired diastolic function

E/V p ≥ 1.5

E/E ′ ≥ 15

E ′ /A

′ ratio <1.0

Peak E ′ velocity <8.5 cm/s

Cardiac TamponadeA. Introduction

The pericardium consists of twosurfaces, the visceral pericardium

which is continuous with the

epicardial surface, and the parietal pericardium which is closely in

contact with the pleural surface

laterally. The pericardial space

Disorder Percentage

Malignant disease

Idiopathic pericarditis

UremiaIatrogenic

Acute MI

SLERadiation

Tuberculosis

MyxedemaDissecting Aortic aneurysm

Postpericardiotomy syndrome

58%

14%

14%3%

3%

2%2%

1%

<1%<1%

<1%

Table 8. Causes of pericardial tamponade

Mitral inflow

PV flow

TDI

CMM-V p



39

normally contains 5 to 10 ml of fluid which may be detected by

echocardiography. This fluid serves as a lubricating material to allow normalrotation and translation of the heart during cardiac cycle.

A wide variety of disorders can result in pericardial effusion. Table 8 shows

some of the main causes of large effusion causing tamponade.When the intrapericardial pressures exceed the pressures in cardiac chambers,

impaired cardiac filling occurs, this is known as tamponade physiology. As the

pericardial pressures increase, filling of each cardiac chamber is affectedsequentially, starting with lower-pressure chambers (atria). The compressive

effect of the fluid is seen best in the phase of cardiac cycle when pressure is

lowest in that chamber (diastole for the ventricle and systole for atrium). Insevere tamponade, diastolic pressures in all cardiac chambers are equal and

elevated.

B. Cardiac Catheterization

Diastolic equilibration or pressures is the hallmark of cardiac tamponade. Hence,accurate measurement of pressures in right and left-sided chambers is mandatorywhen tamponade is suspected, although this is rarely necessary these days with

advent of echocardiography. The pressure tracings should be recorded

simultaneously, along with the

respiratory cycle (Figure 37).

Figure 37. Simultaneous recordings of

aortic (Ao) and the respiratory cycle in

a patient with cardiac tamponade.

During inspiration systemic venousreturn is increased and the aortic

pressure is decreased (pulsus paradoxus). This is an exaggeration of

the normal response.

Ideally both right and left heart catheterization should be done to show the

equalization of diastolic pressures in these chambers. However, if PCWP tracingsis of good quality, and if clinical, non-invasive, and hemodynamic data are

consistent with tamponade, left heart catheterization may be omitted.

When the intrapericardial pressure has increased to equal RA pressure cardiactamponade begins. With the rise in intrapericardial (IP) pressure, the venous

pressure rises to maintain intracardiac volume. In early cardiac tamponadewithout pre-existing heart disease, the intrapericardial and RA pressures are equal

but only slightly elevated. Furthermore PCWP (or LA pressure) remains higherthan the RA pressure. When cardiac tamponade becomes more severe, the RA

and IP pressures remain equal and rise progressively as the tamponade gets moresevere. The point at which the RA, and PCWP (or LA pressure) become equal

defines classic cardiac tamponade (this finding is not pathognomonic, other

conditions can cause this equalization such as constrictive pericarditis). RA andPCWP should be recorded simultaneously rather than sequentially (Figure 38).



40

The height to which the venous pressure is elevated depends on the severity of

tamponade. In milder cases, these pressures range from 7-10 mmHg. Inmoderate cases, pressures are 10-15 mmHg and are often accompanied by

reduction in cardiac output and arterial BP. Severe tamponade is characterized by

pressures in the range of 15-30 mmHg usually accompanied by profound

reduction in CO and arterial BP, which at this stage will demonstrate pulsus paradoxus. Often there is a narrow pulse pressure before the drop in peak systolic

pressure.

In establishing the diagnosis of cardiac tamponade, special attention should be paid to the waveform of RA and PCWP tracings. Inspiratory decrease in RA

pressure should be observed. Cardiac tamponade exerts its abnormal pressure on

heart chambers throughout the cardiac cycle. However, ventricular ejection isfaster than venous return, causing cardiac volume to decrease. With this event

there is a slight decline in IP pressure. For this reason, venous return is confined

to the period of ventricular systole that translates to prominence of x descent andabsence of y descent of venous pressure. Thus, in typical tamponade, RA

pressure is elevated and equal toPCWP and shows an inspiratory dropand absence of y descent. This is in

contrast to constrictive pericarditis

which demonstrates a sharp x and y

descents.

Figure 38. PCW and RA pressure tracings

simultaneously recorded in a patient with

cardiac tamponade. Note the equalization of

the pressure tracings throughout therespiratory cycle, with only a mild deviation

during expiration.

C. Echocardiography

Pericardial effusion is easily recognized on 2D echocardiography

as an echo lucent space next to cardiac structures (Figure 39).These effusions are usually diffuse and symmetric in absence of

previous pericardial disease or surgery. M-mode recordings may

be helpful in identifying small effusions. Fibrinous strandingwithin the pericardial fluid and on the epicardial surface may be

seen with recurrent or long-standing disease. Pericardial effusionis considered small when the separation between the two layers of

pericardium is <0.5 cm, moderate when it is 0.5 to 2 cm, and largewhen >2cm.

Figure 39. Parasternal long (A) and short axis (B) views of a large posterior

pericardial effusion (PE). (Otto, 2000)

A



41

The effusion may be loculated as seen in postoperative patients and in those with

recurrent disease. It is important to note that hemodynamic compromise can

occur with even small loculated effusions. Drainage of loculated effusions maynot be feasible using percutaneous techniques. Care should be taken to

distinguish a pleural effusion from pericardial effusion. A left pleural effusion

will extend posterolateral to the descending aorta, whereas pericardial effusionwill track anterior to the descending aorta (best seen in parasternal long-axis). In

the apical four-chamber view, an isolated echo-free space superior to the RA

likely represents pleural fluid. The subcostal view is useful during echo-guided

pericardiocentesis. Echocardiographic signs of cardiac tamponade are discussedas follows:

a. RA collapse

When intrapericardial pressure rises above the RA

systolic pressure, inversion and collapse of the RA free

wall occurs. The longer the duration of this collapsewhen compared to the cycle length, the greater the

likelihood of cardiac tamponade. Inversion or collapse

greater than 1/3rd

of RA systole (this happens in

ventricular diastole) has a sensitivity of 94% andspecificity close to 100% for diagnosis of tamponade.

Careful frame-by-frame analysis of the 2D images is

necessary for this evaluation.

b. RV Diastolic collapse

This occurs when the intrapericardial pressure exceeds

RV diastolic pressure (Figure 40 & 41). The RV free

wall needs to be of normal thickness and compliancefor this event to take place. RV diastolic collapse is

best seen in parasternal long-axis or from subcostalview. M-mode can be used to assess this phenomenon

more carefully. In cases of tachycardia onset of

diastole is better timed with MV opening and is best

appreciated on M-mode view through MV leaflets andRV. Presence of this sign is 60 to 90% sensitive and 85

to 100% specific for diagnosis of cardiac tamponade.

Figure 40. Parasternal long-axis (A) and short axis (B) views showing RV diastolic collapse (arrows)

(Otto, 2000).

c. Respiratory variations in diastolic filling

With inspiration the LV diastolic filling velocity decreases and theRV early diastolic filling increases (Figure 41 & 42). A decrease in

mitral inflow E velocity greater than 25% has a high sensitivity and

specificity for diagnosis of cardiac tamponade.



42

Figure 41. Schematic representation of LV and RVdiastolic inflow with tamponade physiology showing

enhanced RV (and reduced LV) diastolic filling with

inspiration and a reversal of this phenomenon inexpiration.

Figure 42. A. M mode

tracing showing reciprocal

changes in RV and LVvolumes with respiration

when tamponade is present. B. Doppler

recording of LV inflow in

a patient with tamponade

showing reduced fillingduring inspiration. (Otto,

2000)

d. IVC plethora

A dilated IVC (Figure 43) with <50% reduction in

diameter with inspiration near the IVC-RA junction(subcostal window) reflects an elevated RA

pressure seen in tamponade. This finding is 97%

sensitive but only 40% specific for diagnosis ofcardiac tamponade.

Figure 43. Dilated IVC seen from the subcostal window

(From Otto, 2000).



43

Constrictive PericarditisA. Introduction

Table 9. Causes of Constrictive pericarditis

In constrictive pericarditis, the two layers

of pericardium are joined, fibrous, andthickened. This results in an impairment

of ventricular diastolic filling. Maincauses of constrictive pericarditis are

listed in table 9. Constrictive pericarditis

occurs in approximately 0.2% of patientsafter cardiac surgery.

The typical hemodynamic picture is of

markedly elevated ventricular diastolic

pressures with characteristic pattern of rapid early diastolic filling that stopsabruptly as the limit of ventricular expansion is achieved. This results in an early

dip in the RV pressure tracing, followed quickly by an equally rapid rise in pressure followed by a plateau as the limitation to filling is reached (the so called square-root sign).


Cardiac catheterization is used to assess patients suspected of having constrictive

pericarditis for (1) presence of elevation and equalization of diastolic filling

pressures, (2) effect of constrictive pericarditis on stroke volume and cardiacoutput, (3) evaluation of systolic function, (4) discrimination between constrictive

pericarditis and restrictive cardiomyopathy, and (5) regional outflow tract orcoronary compression by the fibrotic pericardium. Both RV and LV should be

catheterized to allow for simultaneous recording of filling pressures in right andleft heart. Typical findings include elevation and equalization (within 5 mmHg)

of RA, RV diastolic, LA (i.e. PCWP), and LV diastolic pressures before the a wave. The RA pressure recording (Figure 44) is characterized by preserved

systolic x descent, a prominent

early diastolic y descent, and a and v waves that are small and

equal in height (resulting in

typical M or W configuration).

Figure 44. RA pressure recording

from a patient with constrictive pericarditis. There is a prominent y

descent in the pressure waveform.

The prominent X and Y descents givethe waveform the characteristic M or

W shape.

Infectious diseases

Bacterial, mycobacterial, fungalViral

Parasitic

Connective Tissue Diseases

RA, SLETrauma

Blunt or penetrating cardiac trauma

SurgeryRadiation Tx

Neoplastic diseases



44

Both the RV and LV diastolic pressures show an early diastolic dip followed by a plateau (Figure 45). This is the so called square-root sign and may be obscured

by the presence of tachycardia. Another sign seen in constrictive pericarditis is

the reciprocal changes seen in the RV and LV pressures with respiration

(ventricular interdependence). Number of traditional hemodynamicmeasurements for diagnosis of constrictive pericarditis are shown in tables 10 and

11. Unfortunately these signs are not very specific for diagnosis of constrictive

pericarditis with the exception of ventricular interdependence.

Figure 45. LV and RV (A), and LV and PCW (B) tracings from a patient with constrictive Pericarditis. Note the discordant changes in LV and RV pressures (ventricular interdependence) and variability in the

early diastolic PCW-LV gradient with respiration; this represents dissociation of intrathoracic and

intracardiac pressures.

Table 10. Hemodynamic criteria comparison for diagnosing constrictive pericarditis

Criteria Sensitivity (%) Specificity (%) LVEDP – RVEDP ≤ 5 mmHg

RVEDP/RVSP >1/3 PASP <55 mmHg

LV RFW ≥ 7 mmHg

Respiratory change in RAP <3 mmHgVentricular interdependence

60

9393

93

93100

38

3824

57

4895

RFW (rapid filling wave), PASP (PA systolic pressure)

Table 11. Comparative hemodynamics between constrictive pericarditis and restrictive CM

Criteria Constrictive Pericarditis Restrictive Cardiomyopathy End-diastolic pressure equalization

PA pressure

High RVEDP Dip plateau morphology

LV and RV pressures

LVEDP – RVEDP ≤5 mmHg

PASP <55 mmHg

RVEDP/RVSP >1/3LV rapid filling wave >7mmHg

Ventricular interdependence

LVEDP – RVEDP > 5 mmHg

PASP ≥ 55 mmHg

RVEDP/RVSP ≤1/3LV rapid filling wave ≤7 mmHg

Ventricular concordance

C. Echocardiography

2D echocardiography typically shows a thickened pericardium. There is also LA

enlargement due to chronic LA pressure elevation. The pericardium should be

examined from different windows, since pericardial thickening may beasymmetric. M-mode recording done from parasternal window (Figure 46) may



45

show abrupt posterior motion of the LV septum in early diastole and abrupt

anterior motion following atrial contraction. This is due to an initial rapid RVdiastolic filling, followed by equalization of RV and LV filling (plateau phase),

followed by an increase in RV filling after atrial contraction. On subcostal views

the IVC and hepatic veins are dilated, reflecting an elevated RA pressures.

Figure 46. M-mode in constrictive pericarditis showing

rapid anterior motion of the septum (arrow) with atrial

contraction before QRS (From Otto, 2000).

Doppler findings of constrictive pericarditis are

shown in Figure 47. Both RV and LV diastolic

filling show a high E velocity due to rapid earlydiastolic filling occurring simultaneously with the

initial high atrial to ventricular pressure difference

during the brief early diastolic dip in ventricular pressure. As LV pressure rises, filling ceases

abruptly causing a short deceleration time of E velocity. Due to the elevated LV

diastolic pressure, very little late diastolic filling occurs, giving rise to a verysmall A velocity following atrial contraction. Marked reciprocal respiratory

variations are seen in this condition. With inspiration, the intrapleural pressure

becomes more negative, augmenting the RV diastolic filling and inflow velocity.

LV filling velocity decreases with inspiration and increases with expiration.Another change with constrictive pericarditis is the

increase in the IVRT (measured from AV closure to

MV opening) by >20% with inspiration.

Figure 47. Doppler flow patterns in constrictive pericarditis.

LV inflow shows reduced early diastolic filling with

inspiration, while pulmonary vein (PV) shows a prominent a wave (atrial reversal) and blunting of systolic phase (From

Otto, 2000)

Table 12. Doppler findings in constrictive pericarditis and restrictive CM.

Normal Constrictive Restrictive

Respiratory variation in Ein mitral inflow

0-10% ≥25% 0-10%

DT in mitral inflow ≥160 msec ≤160 msec <160 msec

Systolic (S) and diastolic

(D) flows in Hepatic vein flow

S>D in NSR

S<D in AF

↓ in D flow with

expiration

S<D

Systolic (SR) and diastolic

(DR) flow reversals inhepatic vein flow

Slight ↑ in SR and DRwith expiration

Marked ↑ in DR withexpiration

↑ in SR and DR withinspiration



46

Comparison between constrictive pericarditis and restrictive cardiomyopathy

based on 2D echo and Doppler studies are shown in table 12.

Restrictive PhysiologyA. Introduction

Restrictive cardiomyopathy is characterized by a normal LV systolic functionwith an impaired diastolic function secondary to a stiff ventricle. In many

patients with restrictive disease right sided failure symptoms predominate. Table13 shows the common etiologies for restrictive cardiomyopathies. It is important

to remember that restrictive cardiomyopathies are rare when compared with other

causes of heart failure.

Table 13. Classification of Restrictive Cardiomyopathies.

Myocardial

Non-infilterative (Idiopathic, Scleroderma)

Infilterative (Amyloidosis, Sarcoidosis, Gaucher disease, Hurler disease)

Storage Diseases (Hemochromatosis, Fabry disease)Endomyocardial

Endomyocardial fibrosis

Hyperesoinophilic syndrome (Löfflers)Carcinoid

Malignancies

Radiation

Anthracycline toxicity

Post heart transplantation


Restrictive CM can be defined as a primary or secondary myocardial disorderwithout ventricular dilatation and without significant ventricular hypertrophy in

which abnormality in myocardial compliance produces diastolic dysfunction that

closely mimics constrictive pericarditis. The patient typically presents withdyspnea, elevated JVP with prominent x and y descents, and peripheral edema.

The RA pressure tracing is indistinguishable from that of constrictive pericarditis,

and ventricular pressure tracings show the typical dip-plateau configuration

(Figure 48). When a large diastolic pressure difference is found between LV andRV during cardiac catheterization, the diagnosis is more likely to be restrictive

CM than constrictive pericarditis. However, equalization of diastolic pressures in

the two ventricles are just as consistent with constrictive pericarditis or restrictiveCM. Patients with restrictive disease typically have LV filling pressures that

exceed RV filling pressures by more than 5 mmHg; this difference is accentuated

by exercise, fluid challenge, and Valsalva maneuver (not all patients demonstratethis). The PA systolic pressure is often greater than 55 mmHg in patients with

restrictive disease but is lower in patients with constrictive pericarditis.

Furthermore, the plateau of RV diastolic pressure is usually at least 1/3rd

of the peak of RV systolic pressure in patients with constrictive pericarditis, whereas it

is frequently less in patients with restrictive CM. It should be noted that in up to

25% of patients the difference (between constrictive pericarditis and restrictive



47

CM) can not be made on the basis of hemodynamic grounds, and further

information (endomyocardial biopsy or pericardial biopsy) is required fordifferentiation.

Figure 48. Tracings of LV, RV and PCW pressures from a patient with restrictive cardiomyopathy. Note

the concordant changes in LV and RV pressures, despite end-diastolic pressure equalization and dip plateaumorphology. There is also a lack of variability in the early diastolic PCW-LV gradient with respiration.

C. Echocardiography

Echocardiographic imaging in patients with restrictive cardiomyopathy, reveal anon-dilated, thick-walled LV with preserved systolic function and abnormal

diastolic function. Biatrial enlargement is often seen and secondary signs of

pulmonary HTN may be present including paradoxical motion of septum and TR(Figure 49 and 50). Doppler evaluation reveals moderate pulmonary HTN on the

basis of time to peak velocity in the pulmonary artery, and an elevated RVSP

(using TR jet and estimated RA pressures based on IVC plethora and respiratory

variation).

Figure 49. Echocardiographic features ofrestrictive cardiomyopathy (Thick walled, small

LV; impaired diastolic function; LA and RA

enlargement; and signs of secondary pulmonaryHTN including paradoxical septal motion and a

high velocity TR jet). (From Otto, 2000).

Early in course of the disease, impaired

diastolic relaxation of the LV results in impaired early diastolic filling, and theMitral inflow Doppler curve show a reduced E velocity, increased A velocity,

prolonged IVRT, and decreased deceleration slope. PV flow curve shows a

reduced diastolic filling phase and a normal systolic filling phase (resulting in adecreased ratio). As the disease progresses, LA pressure rises, resulting in an

increased pressure gradient between LA and LV. The mitral inflow curve shows

an increased E velocity and a rapid deceleration slope. The A velocity is



48

decreased. This pseudonormal pattern can be distinguished from normal by (1)

the rapid early diastolic deceleration slope, (2) Clinical data (age, presentation,symptoms, etc.), and (3) Pattern of pulmonary venous inflow. With

pseudonormal pattern there is an increase in atrial flow reversal, an increase in

diastolic phase, and a decrease in the systolic phase (Figure 50).

Figure 50. Apical four chamber view of patient with restrictive

CM due to amyloidosis. There is biventricular hypertrophy and

biatrial enlargement. (From Otto, 2000)

Examination of the RA filling by Doppler interrogation of the Hepatic vein

(Figure 51) can be helpful. This shows a prominent reverse flow with atrial

contraction (a wave) followed by a rapid filling curve in systole ( x descent). Thediastolic phase of RA filling is blunted corresponding to a diminished v wave and

y descent.

Figure 51. LV diastolic filling (A) in a patient with restrictive

cardiomyopathy shows an increased E velocity and reduced A

velocity consistent with pseudonormalization. This pattern can be distinguished from normal by the pulmonary venous inflow

pattern (B), showing reduced systolic flows, increased

antegrade diastolic flow (D) and a prominent atrial reversal

(A). (From Otto, 2000)

To summarize, typical Doppler findings in restrictive cardiomyopathy are as follows:



49

Table 14. Doppler echocardiographic findings in Restrictive CM

(M = mitral, T = tricuspid inflows)

Increased E velocity (M>1 m/s; T>0.7 m/s)Decreased A velocity (M<0.5 m/s; T<0.3 m/s)

Increased E/A ratio (>0.2)

Decreased IVRT (<70 msec)Decreased A duration

(Pulmonary and Hepatic inflows)

Systolic velocity much smaller than diastolic velocityIncreased diastolic flow reversal in the hepatic vein during inspiration

Increased atrial flow reversal and duration in pulmonary vein

Finally Table 12 and Figure 52

provide distinguishing features

between cardiac tamponade,constrictive pericarditis, and

restrictive cardiomyopathy.

Figure 52. Diagram showing Doppler

velocities from mitral inflow, tricuspidinflow, and hepatic vein. These are

accompanied by ECG and respirometer

recordings indicating inspiration (i) and

expiration (e). D, diastolic flow; DR,diastolic flow reversal; DR, deceleration

time; S, systolic flow; SR, systolic flow

reversal; Blackened areas under curve,flow reversal. (From Oh, 1999)

Table 15. Comparison of Pericardial Tamponade, Constrictive Pericarditis, and Restrictive Cardiomyopathy

Valvular Lesions

Mode of Assessment Pericardial Tamponade Constrictive Pericarditis Restrictive CMHemodynamics

RAP

RV/LV filling pressures

PA pressure

RV diastolic pressure

plateau

↑

↑, RV=LV

Normal

↑

↑, RV=LV

mild elevation (35-40mmHg systolic)

>1/3 peak RV pressure

↑

↑, LV>RV

moderate to severe elevation(≥60 mmHg)

< 1/3 peak RV pressure

2D Echocardiography Moderate-large pericardial

effusion

Pericardial thickening

without effusion

LVH with normal systolic

function

Doppler 1) Reciprocal resp. changes

in RV and LV filling

2) IVC plethora

1) E>A on LV inflow

2) Prominent y descent in

hepatic vein3) Prominent a wave and

reduced systolic phase in

PV flow

4) Respiratory variation inIVRT and E velocity

1) Early in disease E<A on

LV inflow

2) Late in disease E>A3) Constant IVRT

4) Absence of significant

respiratory variation

Other diagnostic tests Pericardiocentesis CT or MRI for pericardial

thickening

Endomyocardial Biopsy,

MRI



50

Aortic StenosisA. Introduction

Aortic stenosis results in progressive LVOT obstruction. The sequelae of this is

compensatory LVH, classic triad of symptoms (angina, syncope, CHF), and

sudden death.

Table 16. Causes of Aortic Stenosis

CongenitalBicuspid

Unicuspid

AcommissuralOther (e.g. quadracuspid)

Degenerative conditions

Rheumatic

Active infective endocarditisOther conditions

Homozygous type II hyperlipoproteinemiaMetabolic or enzymatic (e.g. Fabry’s disease)

SLE

Figure 53 shows the result from surgical series showing the different etiologies of

valvular AS in patients younger and older 70. Currently the commonest cause of

AS is degenerative (premature degeneration in bicuspid AV and the so calledsenile degeneration of tricuspid AV). If the cause of AS is rheumatic, a careful

search for mitral disease should be made.

> 70 years old

Bicuspid

27%Post inflammatory

23%

Degenerative

48% Unicommissural

0%

Indeterminate

0%

Hypoplastic

2%

Figure 53. Etiology of AS, shown for two age groups. Among patients younger than 70 (left),

calcification of congenitally bicuspid valves accounted for half of the surgical cases. In contrast,in those older than 70 (right), degenerative calcification accounted for almost half the cases. (From

Braunwald, 1997).


< 70 years old

Bicuspid

50%

Post inflammatory

25%

Degenerative

18%

Unicommissural

3%

Indeterminate

2%

Hypoplastic

2%



51

An estimate of severity of aortic stenosis is obtained from the gradient across the

valve. However the pressure gradient does not take into account the cardiac outputwhich, if reduced, results in a smaller pressure gradient. This is seen clearly in

patients with severe left ventricular impairment secondary to AS or coronary disease

who may have no significant transaortic gradient. The gradient across the valve is

also dependent on the time available for the flow of blood to take place; this is thesystolic ejection period (SEP). R. Gorlin and his father G. Gorlin recognized that the

flow is dependent on the pressure gradient. They used a hydraulic model to calculate

the valve orifice size. The Gorlin formula is based on the following relationship:

Q = A x V x C c or A = Q ___

V x C c

Where A is the anatomic area of the valve, Q is the flow during the period that a

given valve is open (SEP for AV), V is the velocity of flow, and C c is a constant oforifice contraction relating functional to anatomical valve area. Velocity of flow (V)

is represented by the following formula,

ghC V v 2= or hC V v 1960=

Where V is the average velocity of transvalvular flow, Cv is a second constant for

viscous frictional losses, g is acceleration due to gravity (9.8 m/s2), and h is the mean

pressure gradient across the valve in cm of water. Then by substituting andcombining Cc, Cv, and 1.166 (the square root of the conversion factor from mmHg to

cm of water) into a comprehensive constant, K , a simplified Gorlin equation is

obtained as follows:

A = Q ______ K x 44.3√ MVG

Where, MVG is the integrated valve gradient. In addition to the above equation Q

(flow) refers to the cardiac output divided by the number of seconds per minute

occupied by the transvalvular flow. Thus,

Q = CO ( ml/min )_____ For aortic and Pulmonic valves

SEP (s) x HR (beats/min)

Q = CO ( ml/min )______ For mitral and tricuspid valves

DFP (s) x HR (beats/min)

Where SEP is systolic ejection period and DFP is the diastolic filling period. Note

that the cardiac output (CO) is in ml/min.

Once the empiric constants are substituted we get the following formula,



52

A = CO ( ml/min )/(SEP x HR)

K x 44.3 √ MVG

Where K is the combined constant and is 1.0 for aortic, Pulmonic and tricuspid valves

and 0.85 for mitral valve. Note that the CO is in ml/min [Hence must multiply CO(l/min) by 1000]

AVA (cm2 ) = CO ( ml/min )/SEP x HR

44.3√ MVG

Measurements of AVA (aortic valve area) using the above formula are inaccurate atlow and high heart rates, at low and high cardiac outputs, and in the presence of

irregular rhythms. The Gorlin formula is also invalid in presence of valvular

regurgitation. The MVG is measured by planimetry of the superimposed aortic andLV pressure tracings in systole (Figure 54). SEP is also measured from this tracing

and used to calculate the valve area. It should be noted that if femoral artery pressuretracing is used there will be a delay in pressure transmission and this artificiallyincreases the gradient. Modifications of the widely used Gorlin formula have been

made. To estimate aortic valve area, the Bache formula uses either the peak-to-peak

or the maximum systolic gradient, thus avoiding planimetry. Hakki omits the ejection

or filling period and the empirical constant. He uses the square root of either themitral mean, aortic mean, or aortic peak pressure gradients divided into the cardiac

output.

AVA (cm2 ) = CO (l/min)_____

√ peak-to-peak gradient

The quick formulas for valve area differ from the Gorlin formula by 18 ± 13% in

patients with bradycardia (<65 bpm) and tachycardia (>100 bpm). The Hakkisimplification of the Gorlin formula can be used to get a quick estimate of AVA.

AVA (cm2 ) = CO (l.min)

√ MVG

For HR >90 one can use the Angel modification of Hakki simplification can be used

for calculation of AVA

AVA = AVA (by Hakki)

1.35

AVA = ___CO____ for HR> 90

1.35√ MVG

Bache



53

Figure 54. Various

methods of describingan aortic transvalvular

gradient. The peak

instantaneous gradient is

the maximal pressuredifference between

Aorta and LV when the pressures are measured

at the same moment.The peak-to-peak

gradient is the

difference between the

maximal pressure in theaorta and the maximal

pressure in LV. The

mean gradient (dashed

area) is the integral of the aortic and LV pressure difference in systole. SEP is the systolic ejection

period.

C. Echocardiography

a. Measurement of gradient

Maximum aortic jet velocity (Vmax) can be used to calculate the maximum

transaortic pressure gradient using the simplified Bernoulli equation:

∆ P max = 4V max2

The mean pressure gradient (∆Pmean) is calculated by digitizing the aortic jet

velocity curve (where v1,v2, …, vn, are instantaneous gradients over the

systolic ejection period, then

∆ P mean = 4v12 + 4v2

2+ 4v3

2 + … + 4vn

2

n

In native aortic valve stenosis transaortic pressure gradients correlate closely

and linearly with maximum transaortic gradients so that the mean pressuregradient can be approximated based on regression equations as

∆ P mean = 2.4 V max2



54

Doppler derived pressure gradients are highly accurate, with an excellent

correlation with catheter-derived pressure gradients across the LVOT (Figure55). This figure shows simultaneous intracardiac pressure tracings (LV and

Ao) and Doppler measurements of a stenotic AV. The two techniques show

an excellent

correlation. However there is

no correlation

between theDoppler derived

gradients and

peak-to-peakgradient derived in

the catheterization

laboratory. Thereis a dependence of

pressure gradientson volume flowrate and this

dependence can

lead to erroneous

conclusions about severity of disease. Hence a patient with coexisting ARand AS will have a high transaortic pressure gradient with only a moderate

degree of valve narrowing. Conversely a patient with LV systolic dysfunction

or coexisting MR may have a low transaortic pressure gradient despite severeAS. Since these coexisting conditions are common in adults determination of

stenotic orifice area is necessary for complete evaluation of disease severity.In other words the estimated valve area is influenced by the flow across the

valve as well as the pressure gradient.

b. Valve area determination

AVA is calculated based on the principle of continuity of flow. Hence the

stroke volume (SV) just proximal to the aortic valve (SVLVOT) and that in thestenotic valve orifice (SVAo) are equal

SV LVOT = SV Ao

If the assumption is made that the flow is laminar with a flat velocity profile,

SV = CSA x VTI

Where, CSA is the cross-sectional area of flow (cm2), SV is the stroke volume

(cm3), and VTI is the velocity-time integral (cm). Since flow both proximal

and distal to the stenosis is laminar with flat velocity profile,

CSA LVOT x VTI LVOT = CSA Ao x VTI Ao

Doppler



55

All of the above variable can be measured from 2D or Doppler

echocardiography except CSAAo which is the AVA. Rearranging the formula,

AVA = CSA LVOT x (VTI LVOT /VTI Ao )

Figure 56. Use of continuity

equation for calculation of

AVA requires measurement of

LVOT diameter for circularcross-sectional area (CSA)

(CSALVOT = π/4 x dLVOT2) from

parasternal long-axis view (A),

PW Doppler determination of

LVOT time velocity integral(VTI) from an apical approach

(B), and CW Doppler

recording of the AS VTI fromwhichever window gives thehighest velocity signal(C).

(From Otto, 2000)

CSA of LVOT is calculated as CSA LVOT = π (d LVOT )2

2

= π x d LVOT 2

4

= 0.785 x d LVOT 2

The measurements needed to calculate AVA using the above equation are (Figure 56):

1) CSA of LVOT calculated from diameter in parasternal-long axis view

2) VTI in the outflow tract, recorded with PW from apical view

3) VTI in the AS jet, recorded with CW Doppler at multiple views until a maximumvalue is recorded (including right parasternal, and suprasternal views

Table 17. Echocardiographic signs of severe AS

Severe AS (in normal systolic function)1. peak AV velocity ≥4.5 m/s

2. mean pressure gradient ≥50 mmHg

3. AVA ≤0.75 cm2 LVOT/AV TVI ratio is ≤0.25



56

Table 18. Grading of AS severity

c. Severe AS with accompanied by LV systolic dysfunction

It is widely accepted that evaluation of AS severity in patients with

significant LV dysfunction with routine echocardiography as described

above is problematic. Low transaortic volume flow rate gives rise to a low pressure gradient across the valve. There is also some evidence that

despite the notion that AVA is less flow dependent, it can vary in parallel

with flow rate and thus may appear reduced with presence of LVdysfunction, even if AS is not severe.

One approach is to increase flow rate across the valve by infusion of low

dose dobutamine (infused gradually from 5 µg/kg per minute in 5µgincrements every 3 minutes up to 20 µg/kg per minute). An increase in

valve area (with dobutamine) reflects leaflet flexibility, whereas fixed

valve area indicates stiff leaflets that can not open anymore. Hence in

patients with true severe AS, infusion of dobutamine increases peakvelocity and VTI of both LVOT and AV proportionally (i.e. LVOT/AV

VTI ratio remains relatively constant), whereas the LVOT/AV VTI ratio

increases with functionally severe AS (or pseudo severe AS). Thedobutamine infusion is stopped when LVOT velocity or VTI reaches a

normal value, 0.8-1.2 m/s or 20-25 cm, respectively. This approach has

several limitations including interpretation of data in cases when flow rateis unchanged.



57

Aortic Regurgitation

A. Introduction

Aortic regurgitation may be caused by primary disease of either the aortic valve

leaflets or the wall of the aortic root, or both. Of patients with isolated ARrequiring valve replacement, close to 50% have aortic root disease as the cause.

Table 19. Causes of Aortic regurgitation

Abnormal valve

Congenital bicuspid

RheumaticInfective endocarditis

Trauma

Floppy AV

SLERheumatoid arthritis

Abnormal aorta and normal valve

Idiopathic aortic root dilatationMarfan’s syndrome

Aortic dissection

Normal aorta and normal valve

Systemic hypertension

Prolapse due to VSDAbnormal aorta and abnormal valve

Ankylosing spondylitis, RA, SLE

Marfan’s syndrome

Ehlers –DanlosOstegenesis imperfecta

Syphilis (i.e. aortitis with commissural separation)

Table 19 lists the causes of AR. Rheumatic fever is the commonest cause of

primary disease of valve leading to regurgitation. The cusps become infiltrated with

fibrous tissue and retract. This process prevents cusp apposition in diastole leading toregurgitation. The associated fusion of commissures will lead to combined AS and

AR. Associated mitral valve disease should be sought.

When aortic annulus becomes greatly dilated, the aortic leaflets separate, and AR

may ensue. Dissection of the diseased aortic wall may occur and will oftenexacerbate the associated aortic insufficiency. Regardless of the cause, AR produces

dilatation and hypertrophy of LV, dilatation of MV ring, and sometimes dilatationand hypertrophy of LA.



58

Table 20. Natural history of aortic regurgitation

1. Asymptomatic patients with normal LV systolic function

Progression to symptoms and/or LV dysfunctionProgression to asymptomatic LV dysfunction

Sudden death

2. Asymptomatic patients with LV systolic dysfunction

Progression to cardiac symptoms3. Symptomatic patients

Mortality rate (with surgery)

<6% per year<3.5% per year

<0.2% pear year

>25% pear year

>10% per year


a. Acute aortic regurgitation

Acute AR does not allow sufficient time for myocardial adaptation, andLV moves quickly up its diastolic pressure-volume curve, causing a

marked elevation of LVEDP and early closure of mitral valve (Figure 58).

There is minimal increase in LVED volume or fiber length, and the totalstroke volume cannot increase sufficiently to compensate for theregurgitant volume; thus forward SV and CO fall. The high LVEDP also

serve to minimize the run-off into LV, therefore the diastolic pressure in

the aorta may remain near normal and the arterial pulse pressure increasesvery little, if at all.

b. Chronic aortic regurgitation

In this case, the LV has time to adapt to the volume overload by using the

Frank-Starling mechanism (increase fiber stretch). The hemodynamic and

afterload conditions in chronic AR (Figure 57 and 58) resemble those of

chronic MR with two important differences: (1) the total SV is ejected intoa high-impedance circuit (the aorta and systemic arteries), and because the

total forward SV is augmented, the LV and aortic systolic pressures are

elevated (>160 mmHg); and (2) because the AV is incompetent, thediastolic pressure in the aorta falls to subnormal levels during diastole,

thereby reducing the diastolic perfusion pressure across the coronaryarterial bed. Because eccentric myocardial hypertrophy is associated with

a sizeable increase in total myocardial oxygen demand, patients with AR

are particularly prone to develop angina in absence of CAD.



59

Figure 57. Severe AI showing a rapidly increasing LV diastolic pressure and the end diastolic equilibration

of aortic and LV pressures.

Figure 58. Schematic representation contrasting the hemodynamic, echocardiographic (M-mode), and

phonocardiographic (PCG) manifestations of acute severe (A) and chronic severe (B) aortic regurgitation.

Ao, aorta; EDP, end-diastolic pressure; f, flutter of anterior mitral valve leaflet; AML, anterior mitral valveleaflet; PML, posterior mitral valve leaflet; SM, systolic murmur; DM, diastolic murmur; C, closure point

of mitral valve. (from Braunwald, 1997)

C. Echocardiography

It has been shown in multiple studies that Doppler assessment of AR hassensitivity and specificity greater than 90% when compared with angiography.

Given these numbers echocardiography is an ideal noninvasive technique for

assessment of AR. Several echocardiographic methods are used for assessing theseverity of AR, these are listed in table 21.



60

Table 21. Echocardiographic approach to AR

a. Assessment of jet area and jet length (Color flow mapping)

Color flow imaging of AR is best performed from the parasternal long and

short axis views. When compared with aortic angiography, the maximalextent or length of the regurgitant jet is poorly correlated with the

angiographic severity of AR.

Figure 59. Diagram showingcolor-flow imaging to estimate

severity of AR. LVOH, LV

outflow height; RJA, regurgitant jet area; JH, jet height. (From

Oh, 1999)

However, the regurgitant jet area obtained from the parasternal short axis

view (Figure 59) relative to the LVOT area (from parasternal short axis) at

the level of the aortic annulus correlates best with angiographic severity ofAR. The width of regurgitant jet (from parasternal long axis view) at its

origin relative to the LVOT height was also a good predictor of AR

severity. Generally an AR jet width to LVOT diameter ratio of ≥0.6 and aregurgitant jet area to LVOT CSA ratio of ≥0.6 are considered severe AR.

b. LV response to AR

In response to chronic volume overload and afterload from AR, LV shows progressive dilatation and an increase in sphericity of the LV is seen

(Figure 60). Initially the LV systolic function remains normal. The EF

remains normal (as opposed to hypernormal in MR) since the total LVstroke volume is ejected into a high-impedance systemic circulation.

Valve anatomy, etiology of regurgitation

Severity of AIFlow mapping (color or PW)

CW Doppler

Descending aorta diastolic flow reversal

Regurgitant volume and fractionMitral inflow pattern

LV response

LV dilatation (end-systolic dimensions)

LV systolic functionAssociated abnormalities



61

Figure 60. Apical four-chamber view (A) and

two-chamber view (B) at end-diastole andsame two views in end systole (C and D) in a

patient with LV dilatation due to chronic AR.

(From Otto, 1999)

With chronic AR the LV size slowly

increases over years withoutimpairment of systolic function. The

LV also remains compliant in diastole

so that the LVEDP remains normal.However, eventual systolic

dysfunction occurs in the presence of

hemodynamically significant chronicvolume overload. End-systolic

volume or dimension provides arelatively load independent measure of ventricular performance. Severalstudies have shown that a LV end-systolic dimension of <55 mm is

predictive of preserved LV systolic function and an excellent prognosis

following AV replacement. There is also a good correlation between

severe AR and LVEDD ≥75 mm.

c. M-mode echocardiography

M-mode echocardiography is helpful in demonstrating premature MVclosure or diastolic opening of AV as a sign of severe, usually acute AR

and a marked increase in LV diastolic pressure. It also demonstrates thefluttering motion of the anterior MV leaflet caused by significant AR

(Figure 61). The regurgitant jet can also be directed against the

interventricular septum. Another M-mode sign is increased E-point septalseparation (EPSS) seen in cases of chronic AR. These signs are neither

sensitive nor specific for the presence of AR. In a large series the

sensitivity of anterior MV leaflet flutter was only 46%, with a specificityof 81%. Interventricular septal flutter was less

sensitive (9%) but had a higher specificity of

90%. The differential diagnosis of mitral leaflet

flutter includes severe MR (even with intactchordae), atrial flutter, and rarely high flow

states such as anemia.

Figure 61. M-mode tracing showing increased E-point

septal separation, and high frequency fluttering of anterior

mitral valve leaflet (arrow) due to impingement by anaortic regurgitant jet. (from Otto, 2000)



62

d. Continuous-wave Doppler

The CW spectral recording of AR has its onset at the closure of AV(during isovolumetric relaxation) with a rapid increase in velocity to a

maximum of 3-5 m/s, followed by a gradual

decline in the velocity during diastole. The

velocity abruptly decelerates during isovolumetriccontraction, reaching baseline at AV opening. The

intensity of the signal, relative to the antegradevelocity, is an indicator of severity of AR.

The CW signal for AR (Figure 62) is best recorded

from an apical window to obtain a parallel

intercept angle between the jet and the blood flowdirection. The slope and pressure half-time (PHT)

of this CW signal have been used to assess the

severity of AR.

Figure 62. CW Doppler recording in two patients, one withchronic AR (A) and one with acute AR (B) showing the

differences in the deceleration slope in each situation. (From

Otto, 2000).

Based on a number of studies it has been suggested that a mean slope of<2m/s in patients with mild AR; a mean slope of 2-3 m/s in groups with

moderate AR; and a mean slope of >3m/s in those patients with severe

AR. A PHT of 400 msec has also been reported to separate mild (1 to 2+)from significant (3 to 4+) regurgitation with a specificity of 92% (a lower

PHT correlating with more severe AR). It should be noted that there are anumber of inconsistencies between these studies and the above numbers

can not be used to provide definitive group separation.

With acute AR, even if only moderate in severity, LV compliance has notyet adapted, as occurs in response to chronic volume overload, so a

significant increase in end-diastolic pressure is seen. This is reflected in a

more rapid decline in slope (Figure 59) when compared to chronic AR.

e. Flow reversal in descending aorta

With severe AR, a holodiastolic flow reversal can be seen in the

descending aorta. This observation is analogous to the Duroziez's sign seen on physical exam (diastolic reversal in femoral arteries). The finding

of diastolic flow reversal in proximal abdominal aorta (Figure 63), is both

sensitive (100%) and specific (97%) for the diagnosis of severe AR. False positive can result from presence of a patent ductus arteriosus. This is best

recorded from the subcostal window.



63

Figure 63. Pulsed Doppler sample volume

(SV) positioned in the descending aorta from asubcostal window (inset). The Doppler

velocity curve shows holodiastolic flow

reversal (arrows) consistent with severe AR.

(from Otto, 2000)

f.

Regurgitant volume and fractionAR volume and fraction can be calculated as the difference betweentransaortic and transmitral volume flow. If there is no significant MR, mitral

valve inflow can be used to represent systemic stroke volume.

MV flow = MV annulus area x MV VTI

MV annulus area = MV annulus diameter 2 x π /4

MV flow = MV annulus diameter 2 x 0.785 x MV VTI

Regurgitant volume is the difference between the SV across LVOT and

MV, therefore

AR volume = LVOT flow – MV flow

AR volume = (LVOT diameter 2 x 0.785 x LVOT VTI) – (MV annulus diameter 2 x 0.785 x MV VTI)

A regurgitant volume ≥60 mls indicates severe AR.

Regurgitant fraction (RF) can be calculated according to the following

equation:

RF = AR volume____ x 100%

LVOT stroke volume

A RF ≥55 % indicates severe AR. The AR orifice area can be calculated by dividing

regurgitant volume by AR VTI.

Effective AR orifice area = AR volume

VTI AR



64

An effective AR orifice area ≥0.3 cm2 indicates severe AR.

Table 22 shows the echocardiographic and Doppler signs associated with severe AR.

Table 22. Echocardiographic signs of severe and mild AR

Mitral Stenosis

A. Introduction

The primary pathophysiologic abnormality in patients with MS is mechanical

obstruction at the mitral valve level. Secondary upstream consequences of MVobstruction include the effects of an elevated transmitral pressure gradient on the

LA and pulmonary vasculature. In isolated MS, the downstream LV is relativelyspared and tends to be normal or small with normal contractile function unless

aortic or mitral regurgitation is also present.

Obstruction at the MV level increases the diastolic pressure gradient between the

LA and LV. As obstruction becomes more severe, the pressure gradientincreases, with mean transmitral gradients at rest of 10 to 25 mmHg in patients

with severe MS. In addition to the severity of the mitral obstruction, transmitral

pressure gradients also depend on the volume flow rate across the valve indiastole. For a given valve area, a higher transmitral gradient occurs with an

elevated transmitral flow rate, for example, with fever, anemia, during exercise, orwith coexistent MR.

Table 23 lists the causes of MS. The commonest cause by far is rheumatic

MS. The most characteristic finding for rheumatic MS is fusion of leaflet edges

along the commissures between the anterior and posterior leaflets. Additionalfeatures include fusion, thickening, and shortening of the chordae; fibrous

thickening of the valve leaflets; and superimposed calcific changes. Flow is

obstructed by a combination of reduced leaflet opening caused by commissural

fusion, and increased rigidity of the leaflets as well as by the obstruction at the

Severe AR

Regurgitant jet width/LVOT diameter ratio ≥60%Regurgitant jet area/LVOT area ratio ≥60%

AR PHT ≤250 msec

Restrictive mitral inflow pattern (usually seen in acute AR)

Holodiastolic flow reversal in the descending aorta

Dense CW signalRF ≥55%

AR volume ≥60 ml

LV diastolic dimension ≥75 mm (chronic AR)Effective AR orifice ≥0.3 cm2

Mild AR

Regurgitant jet width/LVOT diameter ratio ≤30%

Regurgitant jet area/LVOT diameter ≤30%AR PHT ≥400 msec

Mild early diastolic flow reversal in descending aorta

Faint CW signalRF <30%

LV diastolic dimension <60 mm

Effective AR orifice <0.10 cm2



65

subvalvular level. Sometimes obstruction can result from severe mitral annular

calcification.

Table 23. Etiology of Mitral stenosis

Rheumatic (>95% cases)

Other causesActive infective endocarditis, with obstruction by vegetation

Mitral annular calcification

Metabolic or enzymatic

Whipple’s disease, mucopolysaccharidosis, Fabry’s diseaseCarcinoid

Methysergide therapy

Congenital

Causes mimicking MSLA myxoma

Cor Tritriatum


With moderate to severe MS, the overall profile of diastolic flow into the LV is blunted so that distinct rapid-filling and slow-filling phases are no longer seen

before atrial systole. The pressure difference between LA and LV is relativelyhigh during early diastole, declines slowly throughout mid and late diastole

(delayed y descent), and then, if normal sinus rhythm persists, the gradient again

augments with atrial contraction (a wave). The height of the a wave depends onthe integrity of atrial contractility and severity of valvular obstruction (Figure 64).

The height of v wave during ventricular systole depends on the compliance of LA,

the rate and magnitude of LA filling, and the presence and magnitude ofcoincident MR.

Heart rate exerts an important influence on the pathophysiologic manifestations of

MS because diastolic flow per minute across MV depends not only on the valvearea and pressure gradient but also on the duration of diastole. As the heart rate

increases there is less time for the atrial and ventricular pressures to equilibrate,

and the mean LA pressures increase (Figure 65).

Figure 64. Simultaneous

recordings of PCW and LV

pressures in a patient with

MS. On the first beat the

atrial contribution is evident.Loss of atrial activity in beat

2 results in loss of the a

wave and a large v wave

with an increased mitralvalve gradient.

In the above figure simultaneous LV and PCW pressures are recorded demonstrating

a mitral valve gradient throughout diastole. The a wave in the first beat is associatedwith a normal v wave. In the following beat, atrial activity is delayed and follows the

QRS, contributing to a large v wave. The augmented filling increases the MV



66

gradient. LA pressure can be measured using transspetal techniques as in figure 62.

When the rhythm is irregular (e.g. atrial fibrillation), calculation of gradients should be made from an average of 10 beats.

Figure 65. LA and LV pressure

tracings in a patient with MS.Shaded area represents the mitral

valve gradient. DFP= diastolic

filling period. The planimeteredarea (shaded) is used to calculate

mean valve gradient (MVG).

MVG = area x scaling factor

DFP

Using the Gorlin formula (see section on aortic stenosis) one can calculate

the mitral valve gradient and area.

A = Q_____

K x 44.3√ MVG

Where Q is the flow during the period (diastole for Mitral valve), MVG isthe mean valve gradient (calculated by planimetered area of LA/PCW and

LV pressure tracings) and K is the combined constant and is 1.0 for aortic,

Pulmonic and tricuspid valves and 0.85 for mitral valve the constant. Formitral valve Q is calculated by:

Q=

CO ( ml/min )______

DFP (s) x HR (beats/min)

Combining the equations:

Mitral valve area (cm2 ) = CO ( ml/min )/DFP x HR

37.7 √ MVG

Figure 66. PCW and LV pressure

tracings in a patient with combined

MS/MR in atrial fibrillation.

Figure 66 shows simultaneous recording of LV and PCW pressures

showing a giant v wave with persistent LV-PCW gradient during diastole.



67

This is the pattern of mixed MS-MR. The slope of v waves in MS/MR is

flatter than that of isolated MR (see MR section).

C. Echocardiography

a.

M-mode echocardiographyAlthough M-mode echocardiography has been used in the past to assess

patients with mitral stenosis, 2D echocardiography is far superior

technique and has superseded M-mode for assessment of mitral valve.Some of the M-mode findings of MS are diminished E-F slope of the

anterior mitral valve leaflet (figure 67) and anterior motion of posterior

mitral valve leaflet in diastole (figure 68). These findings are only ofqualitative importance.

Figure 67. M-mode

echocardiogram of

normal mitral valve

(A) and one of a patient with mitral

stenosis (B). The

mitral leaflet isthickened and the E-F

slope is prolonged

(From Oh, 1999).

Figure 68. M-mode

echocardiogram of a patient with mitral

stenosis. Note the

thickening of the anterior

mitral valve leaflet

(AMV), the reduced E-F

slope, and the anteriormovement of the posterior

mitral valve leaflet (PMV)

during diastole (FromWeyman, 1994).

b. mitral valve gradient

The mean diastolic transmitral pressure gradient can be determined from

the transmitral velocity curve (during diastole) using the simplified

Bernoulli equation



68

∆ P mitral = 4(v12 + v2

2 + v3

2+…+ vn

2 )

n

The mean pressure gradient can be as high as 20 to 30 mmHg with severe

stenosis, but it may be as low as 5 to 15 mmHg. This variability in

pressure gradient in severe MS is due to the dependence of pressuregradient on volume flow rate as well as the valve area. If volume flow

rate is increased with exercisefor example, the transmitral

pressure gradient increases.

Figure 69. Simultaneous LV andLA pressure measurements and

Doppler velocity recordings of

a patient with MS. The peakinstantaneous and the mean

gradients correlate well. (Oh 2000)

Hence calculation of valve

area is required to help assess

the severity of MS.Gradients can potentially be overestimated in patients with AR that is due to

contamination of mitral flow stream with the higher velocity aortic flow. This

problem can be overcome by using color flow mapping to separate the twostreams and placing the sample volume at the mitral orifice.

c. mitral valve area (MVA)

Several methods are used for calculation of MVA by 2D

echocardiographyi. planimetry

Because of simpler geometry of stenotic mitral valve

when compared to aortic valve it is possible to accuratelydetermine the MVA by direct planimetry. Thus 2D short

axis imaging of diastolic orifice is used for this

measurement. The measured values have been compared

in numerous studies to both surgical specimens as well ascardiac catheterization derived MVA values with good

correlation (correlation coefficient r = 0.84 to 0.92). It is

important to start the scan at the apex (parasternal short-axis view), slowly moving the image plane towards the

mitral valve to identify the smallest orifice. The inner

edge is traced (Figure 65).

Figure 70. Parasternal long-axis (above) and short-axis (below)

views of severe mitral stenosis. Note the diastolic doming and severecommissural fusion. Valve area is determined by two-dimensional

planimetry in the short-axis view at the smallest orifice visualized.



69

MVA in this case was 0.5 cm2. In addition there is severe left atrial enlargement (From Otto, 2000).

Figure 71. Schematic diagram of relationship between LA and

LV pressures and the Doppler velocity curve in MS.

Maximum velocity is identified. The patient is in atrialfibrillation (Otto, 2000)

ii. Pressure Half-time method (PHT)

Calculation of MVA by this method is based on the

concept that the rate of decline in pressure across a

stenotic mitral orifice is determined by the cross-

sectional area of the orifice. Hence the smaller theorifice the slower the rate of decline in pressure.

PHT is the time interval (in ms) between the

maximal early diastolic transmitral pressuregradient and the time where the pressure gradient is

half the maximum value. This concept was then

adapted to the transmitral velocity curves (based onthe relationship between velocity and pressure described by Bernoulli equation).

Figure 72. PHT measurement in a patient with severe MS.

The measured PHT of 422 ms corresponds to a valve area of

0.52 cm2 (Otto, 2000) .

Therefore the PHT is determined as the timeinterval from the maximum mitral velocity in

diastole (Vmax) to the point where the velocity is

fallen to Vmax/√2 (Figure 71 and 72). Studiescomparing the Doppler measured data with

catheter determined valve areas using the Gorlin

formula found a linear relationship with a half-time of 220 ms for a valve area of 1cm

2.

Therefore,

MVA (cm2 ) = 220

T 1/2

PHT (T1/2) is always 29% of the deceleration time (DT) which is the

time for peak velocity (Vmax) to reach baseline

T 1/2 = 0.29 x DT



70

Although this method has been used to assess MS in prosthetic

valves, it has only been validated in native valves stenosedsecondary to rheumatic heart disease. Hence care should be taken

when applying the PHT method to stenosed prosthetic MV. PHT

method is also not accurate when applied to patients immediately

after percutaneous mitral commissurotomy or valvuloplasty, due tothe changing atrial and ventricular compliances.

iii. Continuity equationThe continuity principle discussed earlier can also be applied for

calculation of mitral valve orifice area.

MVA = transmitral SVVTI MS-jet

Where SV is the stroke volume in ml, VTI is the velocity-time

integral in cm.

Transmitral SV = CSA LVOT x VTI LVOT

= 0.785 x d LVOT 2 x VTI LVOT

Where dLVOT is the diameter of LVOT measured from the parasternal

long-axis, and VTILVOT is the velocity-time integral in the LVOT (in

the absence of AR) measured from an apical view. Substituting inthe above equation,

MVA = 0.785 x d LVOT

2 x VTI

LVOT

VTI MS-jet

This estimate is accurate only if there is no significant MR.

Table 24. Echocardiographic signs of severe MS

MS severity

1. Valve area

Normal 4-6 cm2 Mild 1.6-2.0 cm2

Moderate 1.1-1.5 cm2

Severe ≤1.0 cm2

2. Resting mean pressure gradient ≥10 mmHg

3. PHT ≥220 msec

iv. PISA

The PISA method can be applied to calculate MVA in MS. (for

complete discussion of the PISA method see section on MR)



71

Figure 73. Diagram of stenotic MV and angle

between the two leaflets (α). Because PISA is

contained between the two mitral leaflets, it isobtained by multiplying the hemispheric area by

the correction factor (α/180).

The MVA is calculated by the PISA method according to the

following equation:

MVA = 6.28r 2 x V aliasing x α˚ __

Peak Velocity MS 180˚

Angle correction factor may not be necessary if the bottom surface

of the hemispheric PISA is relatively flat (i.e. α = 180˚).

Balloon Mitral Commissurotomy

Several factors are important in selection of patients for catheter mitral

valvuloplasty. These are:

1) Does the severity of valve obstruction require intervention

2) Anatomy and morphology of the mitral valve

3) Degree of coexistent MR is considered4) Presence and severity of other valve lesions or CAD are assessed (since if surgery

is needed for these, the stenotic mitral valve can be dealt with at that time)

5) Comorbid conditions or technical considerations that may affect the procedure areevaluated

6)

The patient’s preference for a catheter based or surgical procedure is incorporatedin the decision making process.

The predictors of a poor initial result include older age, smaller baseline valve area,

higher pulmonary pressures, and a smaller area of the dilating balloon. However, theanatomy of the mitral valve appears to be the strongest predictor of both immediate and

long-term outcome. Patients with thin, flexible valve leaflets; little calcifications of theleaflets or the commissures; and minimal chordal involvement have the best

Mitral

Leaflet

Angle ( α ) First Alias

r



72

hemodynamic results and long-term outcome. Patients with heavily calcified and

deformed valves have a poor long-term outcome and are also at a higher risk for procedural death and major complications. The most widely used approach to evaluation

of mitral valve morphology is the composite Massachusetts General Hospital (MGH)

score (Table 25). This score predicts both immediate increase in valve area and restenosis

at 6 month follow-up after valvuloplasty. When the morphology score is considered tohave a cutoff score of 8, a greater valve area increase is seen in group with lower score

(≤8).

Table 25. Massachusetts General Hospital mitral valve morphology scoreGrade Mobility Subvalvular

Thickening

Valvular

Thickening

Valvular

Calcification

0 No restriction None None No areas of echo

brightness

1 Highly mobile

valve with only

leaflet tips

restricted

Minimal

thickening just

below the mitral

leaflets

Leaflets near

normal in

thickness (4-5

mm)

A single area of

increased echo

brightness

2 Leaflet middle and

base portions havenormal mobility

Thickening of the

chordal strucrturesextending up to

1/3rd of the chordal

length

Mid-leaflets

normal,considerable

thickening of the

margins (5-8 mm)

Scattered areas of

brightnessconfined to leaflet

margins

3 Valve continues tomove forward in

diastole, mainly

from the base

Thickeningextending to the

distal 1/3rd of the

chords

Thickeningextending through

the entire leaflet

(5-8 mm)

Brightnessextending into the

midportion of the

leaflets

4 No or minimal

forward movement

of the leaflets indiastole

Extensive

thickening and

shortening of allchordal structures

extending down to

the papillarymuscles

Considerable

thickening of all

leaflet tissue (>8-10 mm)

Extensive

brightness

throughout muchof the leaflet tissue

Produces a total score of 0 to 16.

Other approaches to evaluation of mitral valve morphology that also predict immediate

hemodynamic result is the three group grading (Table 26). This system is primarily

based on the extent of subvalvular involvement and the extent of leaflet calcification.When this system was used for a series of 1512 patients, inadequate hemodynamic results

were seen in only 2.2% of Group 1 and 7.4% of Group 2 patients but in 22.3% of Group

3 patients.

Table 26. The three group grading of mitral valve anatomy Echocardiographic Group Mitral Valve Anatomy

1 Pliable, noncalcified anterior mitral leaflet and mild

subvalvular disease (ie thin chordae ≥10 mm long)

2 Pliable, nonclacified anterior mitral leaflet and

severe subvalvular disease (ie thickened chordae<10 mm long)

3 Calcification of mitral valve of any extent, as

assessed by fluoroscopy, whatever the state of the

subvalvular apparatus



73

Several of these criteria have been combined into an overall criteria forassessment of mitral valve morphology (Table 27). One problem with all these scoring

systems is that the continuous range of mitral valve anatomy is compressed into discrete

categories, so that borderline cases will be classified inconsistently. Further all the

scoring systems are subject to interobserver variability.

Table 27. Two-dimensional echocardiographic assessment of mitral valve morphology

Variable Predicted ResultsOptimal Suboptimal

Leaflet motion Highly mobile with

restriction only of leaflettips, and H/L ratio ≥0.45

Minimal forward motion

of the leaflets indiastole, or H/L ratio

≤0.25

Leaflet thickening Leaflets <4-5 mm or

MV/PWAo ratio of 1.5-2.0

Leaflets >8.0 mm thick

or a MV/PWAo ratio≥5.0

Subvalvular disease Thin, faintly visiblechordae tendinae with

only minimal thickening

below the valve

Thickening andshortening of chordae to

papillary muscle; areas

with echodensity greater

than endocardium

Commissural calcium Homogeneous density

of both commissures

Both commissures

heavily calcified

Finally the general accepted contraindications to mitral valvuloplasty are listed in

table 28.

Table 28. Contraindications to mitral valvuloplasty

Left atrial thrombus

MR >2/4

Massive or bicommissural calcification

Severe aortic valve disease, or severe tricuspid stenosis + regurgitation associated with MS

Severe concomitatnt CAD requiring bypass surgery

Both autopsy as well as echocardiographic data suggest that the splitting of fusedcommissures is the mechanism of the increase in valve area with catheter balloon

commissurotomy. The dilating balloon is advanced from the right femoral vein into the

RA and then, through a trans spetal approach, into the left atrium. This is a potential

source of complications and requires considerable expertise. Echocardiography has beenused for guidance during trans spetal puncture as well as balloon placement (Figure 74).

The balloon dilating catheter is then advanced across the mitral valve. After the correct

position is insured, the balloon is dilated briefly, with one to four inflation needed toachieve an adequate increase in valve area. Balloon sizes are often chosen empirically

based on patient’s size. With a single balloon technique (Inoue), balloon size is chosen

based on the patient’s height. Each balloon allows inflation to several different finaldiameters, allowing a stepwise approach to valve dilation. Figure 76 shows the use of the

Inoue balloon. After the balloon is positioned across the mitral valve, the distal segment



74

in the LV is dilated first, followed by the proximal segment in the LA. This approach

holds the balloon securely in position while the middle (dilating) balloon is brieflyinflated.

Complication of catheter balloon valvuloplasty (Table 29) include, development

of a small ASD (at the site of transspetal approach). This defect is found in over 60% of

patient by color flow Doppler. In most cases the defect closes spontaneously with adetectable shunt visualized in 20-30% of patients at 18 months follow-up evaluation. A

significant shunt across the iatrogenic ASD is uncommon, occurring in only 4-20% in

different series. The most serious complication is cardiac tamponade resulting from perforation by a guiding or dilating catheter. This has been reported in 0.8-4% of cases.

An increase in MR from none or mild at baseline to moderate or severe after the

procedure is seen in 13% of cases (1-8% developed severe MR). The numbers are lowerwith Inoue balloon. Urgent surgical intervention (for tamponade or MR) is needed in

between 0.4-4.8%. Systemic embolization occurs in 0.5-3.3% of patients. This is due to

dislodgement of LA thrombus during the procedure. This risk can be minimized by usingTEE evaluation prior to the procedure.

Univariate predictors of procedural death include older age, history of cardiacarrest, cerebrovascular disease, dementia, renal insufficiency, cachexia, CHF symptomsat rest, smaller valve area, and a higher echocardiographic morphology score.

Table 29. Major complications of balloon mitral valvuloplasty

Procedural mortality 0.1% to 4.5%

Systemic embolization 0.5% to 3.3%

Tamponade 0.8% to 4%

Shunt 4% to 14%

Severe MR 1% to 8%

Immediate surgery 0.4% to 4.8%

Figure 74. TEE guidance of Inoue

balloon mitral valvuloplasty. The

transspetal needle is seen indenting the

atrial septum (arrow) just before puncture(A), followed by positioning of balloon

catheter (arrow) in the left atrium (B).

After the balloon catheter is advancedacross the mitral valve, first the distal

segment of the balloon (arrow) is inflated

(C), followed by a brief inflation (arrow)of the proximal and dilating segments (D).

(From Otto, 1999)



75

Figure 75. Parasternal

short axis view showing planimetered mitral valve

areas immediately before

(A) and after (B) balloon

mitral valvuloplasty.MVA increased from 1.2

to 1.9 cm2 in this case

(From Otto, 1999).

The improvement invalve function results in

an immediate decrease inLA pressure (Figure 77)and a slight increase in

cardiac index. A gradual

decrease in PAP and PVRis seen. When severe MR

complicates the procedure

the LA pressure tracingwill show a large v wave

(Figure 78).

Figure 77. Left atrial (LA) and left ventricular

(LV) pressure before (A) and after (B) balloon

catheter valvuloplasty.

Figure 78. Left atrial (LA) and left ventricular

(LV) pressures in a patient with mitral stenosis before (A) and after (B) balloon catheter

valvuloplasty. Note the larger v waves after the

procedure indicating increase in MR.

Figure 76. Fluoroscopic images

recorded during a percutaneous

balloon valvuloplasty using an Inoue

balloon. (A) the distal balloon has been inflated to secure the position at

the valvular level. (B) The proximal

segment has also been inflated. (C)

The dilating segment is then briefly

dilated. (From Otto, 1999)



76

Mitral RegurgitationA. Introduction

Normal MV closure, which prevents the systolic backflow of blood into the LA,

depends on the complex interaction of each of the components of the valve

apparatus (LA wall, the annulus, the MV leaflets, the chordae, the papillary

muscles, and the LV wall). Abnormalities in the anatomy and function of any ofthese components lead to valvular regurgitation. Table 30 shows the etiologies of

MR classified as those with abnormal valve and those with normal valve.

Table 30. Etiology of mitral regurgitation

Abnormal valve

Floppy mitral valve (Myxomatous degeneration)

RheumaticInfective endocarditis

Connective tissue disorders (Marfan’s syndrome, Ehler Danlos)

Mitral annular calcificationCongenital (cleft often associated with primum ASD or fenestrated)

SLERhematoid arthritis

Radiation therapyCarcinoid syndrome

Pharmacologic agents (e.g. methysergide, fenfluramine-phentermine)

Endomyocardial fibrosis

Normal valve(Subvalvular causes)

Papillary muscle dysfunction (including rupture)Acute or remote MI

Infiltrative myocardial disease (e.g. amyloid, sarcoid)

Hypertrophic and dilated CMSystemic hypertension

Ventricular dilatation (any cause)


Pressure measurements either in the PCW or LA positions usually reveal an

elevated v wave (>20 mmHg peak value), followed by a relatively rapid y descentas the MV opens and an excessive inflow of blood traverses the MV (Figure 79).

There is not uncommonly a small pressure gradient across the MV during early

diastole, reflecting functional MS in the presence of increased flow. If the MR isrelatively acute and severe, a very large v wave is generated owing to the fact that

the LA remains relatively normal sized and noncompliant and LV shortening

remains normal to supranormal. Conversely in longstanding severe MR, the v wave may be extremely small owing to massive dilatation of LA and a significant

increase in its capacitance. When myocardial contractility becomes severelydiminished, depression of the total stroke volume may also contribute to the lackof generation of a significantly elevated v wave.

The effective CO depends on the severity of the regurgitation, the acuteness

versus chronicity of the process, the adaptation of the LV to the volume overload,

and the maintenance of normal myocardial contractility.



77

Figure 79. LV and

LA pressuretracings in isolated,

sever MR and atrial

fibrillation. The a

and c waves in theLA tracing are not

evident and the v wave is

accentuated.

Combined MS and MR is often associated with a heavily calcified valve that haslimited leaflet mobility. Because systolic regurgitation augments antegrade flow

during the subsequent diastole, a transvalvular pressure gradient can develop in patients with a relatively mild compromise of the mitral orifice area(approximately 2.0 cm

2). Significant dilatation of LA is seen owing to the

combined pressure and volume overload of the chamber. In this setting, the

pressure recordings from the left heart reveal an early and mid-diastolic pressuregradient across the MV, but if the DFP is sufficiently long, the LA and LV

pressures equilibrate during the period of slow ventricular filling (Figure 80). The

v wave is often dominant, reflecting the augmented systolic expansion anddilatation of LA. The amount of regurgitation is calculated as the difference

between total LV stroke volume (measured on contrast LV angiogram) and thestroke volume calculated from a Fick or indicator-dilution CO and the resting HR.

Figure 80. LV and

LA pressure tracings

in combined MS and

MR in atrial

fibrillation.

As detailed in Table 31, semiquantitative criteria have been established that, when

combined with clinical and noninvasive diagnostic features, serve to categorize the

severity of a volume overload imposed by valve leakage.



78

Table 31. Assessment of severity of valvular regurgitation by Cine angiography

Grade of Severity Regurgitant Fraction MR AR0 0 No regurgitation No regurgitation

1 + 0.1-0.2 Contrast agent in LA

only near MV; clears in

next diastole

Contrast agent in LVOT

only

2 + 0.1-0.3 Regurgitation to mid LA but not progressive;

contrast agent persists in

LA in next diastole

Contrast agent in LV body; persists for up to 1

beat

3 + 0.2-0.4 Contrast agent fills

entire LA over 2 or 3

beats; LA density lessthan that in LV

Progressively fills entire

LV cavity in 2 or 3

beats; LV density <ascending aorta

4 + 0.4-0.8 Contrast agent fills into

pulmonary veins on 1

beat; LA density ≥ LV

Contrast fills entire LV

on 1 beat; LV density ≥

aorta

C.

Echocardiography

a. Color flow mapping

The area of regurgitant jet relative to the LA size is the most predictive of

severity of MR when compared with angiography (Table 32). Although

MR jet length as well as AR jet area also have good correlation withangiographic data. It should be noted that in the setting of central jets,

color flow mapping over-estimates the MR severity due to the entrainment

phenomenon.

Table 32. Severity of MR as a function of ratio of MR jet area to left atrial area (LAA)

Severity of MR MR jet area/ LAA Sensitivity SpecificityMild <20% 94% 100%

Moderate 20-40% 94% 95%

Severe >40% 93% 96%

b. Vena Contracta

The vena contracta width is defined as the narrowest diameter of

regurgitant flow immediately downstream from the flow convergenceregion. This width more directly reflects changes in the size of the

regurgitant orifice, and unlike proximal jet width, vena contracta remains

accurate in the presence of eccentric jets. The feasibility of measuringvena contracta is 92-97% in patients with MR with minimal inter-observer

variability. An accurate measurement of vena contracta is obtained from

long axis views by TTE or TEE. For MR a vena contracta width of 5 mmor greater identifies severe MR, and a vena contracta width of 3 mm or

less identifies mild MR.



79

c. Continuous wave Doppler

CW recording of MR shows a rapid rise in velocityduring isovolumetric contraction (proportional to dP/dt )

from baseline. With acute MR, a rise in LA pressure

during late systole (v wave) may be present due to a

steep pressure-volume relationship of the non-dilatedLA (Figure 81). Significant MR is also associated with

an increase in antegrade velocity due to an increase inthe transmitral volume flow.

Figure 81. CW Doppler recordings in two patients with chronic

(above) and acute (below) MR. The tracing in acute MR shows a v

wave (arrows). (From Otto, 2000)

d. Volumetric method

In the absence of significant AR, the difference between

flow across MV and the LVOT is the mitral regurgitant

volume.

MV Reg V = MV flow – LVOT flow= (Annulus D

2 x 0.785 x TVI) MV – (D

2 x 0.785 x TVI) LVOT

Where Annulus D is the mitral annulus diameter and D is the LVOT

diameter. The regurgitant fraction (RF) is calculated by dividing Reg V

by flow across MV and multiplying by 100.

MV RF = MV Reg V x 100 (%)

MV flow

The effective regurgitant orifice (ERO) is then

estimated by dividing the Reg V by the VTI of MRvelocity recorded by CW Doppler (Figure 82).

ERO MV = MR RegV

MRVTI

Figure 82. Quantitative evaluation of MR severity by

calculation of transmitral and transaortic volume flow rates.Mitral annulus diameter and VTI of flow across mitral

annulus are used to calculate total stroke volume. Forward

stroke volume is determined from cross-sectional area andVTI of LVOT. (From Otto, 2000)



80

e. Proximal isovelocity surface area method (PISA)

As the blood in the LV converges towards the mitral regurgitant orifice

(Figure 83), the velocity of blood

flow increases and forms a series

of hemispheric waves, whosesurface has the same velocity.

Based on the principle of volumeflow calculation by Doppler

techniques, the regurgitant flow

rate for this surface, when

averaged over temporal flow, is

Figure 83. Flow accelerates proximal to the orifice, resulting inconcentric proximal isovelocity surface areas. The color Doppler

aliasing velocity allows identification of one of these PISAs, whichthen can be used to calculate regurgitant volume (see text)

Regurgitant volume = PISA x Velocity

The PISA velocity can be determined from the color flow image as the aliasing

velocity where a distinct red blue interface is seen. At this interface the velocity isknown and is equal to the Nyquist limit on the velocity color scale. The size of the

PISA can be maximized for more accurate assessment of regurgitant orifice, by

decreasing the velocity range or shifting its baseline (< 30 cm/s). Given that the

shape of the isovelocity surface is hemispherical, PISA can be calculated from themeasurements of the distant from the aliasing velocity to the regurgitant orifice as

(area of a hemisphere):

PISA = 2π r 2

One can determine the effective regurgitant orifice (ERO) using the following

formula,

PISA flow = MR flow

2π r 2

x Velocity PISA = ERO x Peak Velocity MR Velocity PISA = V aliasing

ERO = 2π r 2 x V aliasing

Peak Velocity MR

ERO = 6.28r 2 x V aliasing

Peak Velocity MR

r

Regurgitant

Jet (RJ)

Regurgitant

Orifice

PISA



81

Regurgitant volume (RV) can be then calculated from the ERO by:

RV = ERO x VTI MR

RV = 6.28r

2

x V aliasing x VTI MR Peak Velocity MR

f. Pulmonary vein flow reversal

In severe MR, there may be a systolic flow reversal in the pulmonary vein

(Figure 84); however, the absence of systolic flow reversal in pulmonary

vein does not exclude severe MR. False negative results occur when LAis severely enlarged and compliant so that all the excess volume is

contained in the LA without displacement into pulmonary veins. False

positive results occur when an eccentric jet is directed into a pulmonaryvein, causing flow reversal when MR is not severe.

Figure 84. Pulmonary vein CW Doppler

tracing in a patient with severe MR showing a

systolic flow reversal (SR), D is the diastolic

flow. (From Oh, 1999).

g. Peak mitral inflow velocity

Early diastolic mitral inflow velocity relates directly to the instantaneous

pressure gradient between the LA and the LV. The added regurgitantvolume increases the LA to LV pressure gradient, which in turn increasesthe early mitral inflow velocity (E wave). The peak E wave velocity >1.2

m/s identified patients with severe MR (isolated) with a sensitivity of 85%

and a specificity of 86% (Thomas et al, 1998). It must be mentioned thatincreased mitral inflow velocity has also been observed in patients with

severe AR. Moreover, the predictive value of this marker has not been

tested in patients with acute MR. Therefore, although peak E velocity



82

may be a simple screening method for hemodynamically significant MR,

it should not be used in isolation to judge the severity of regurgitation.

Table 33. Echocardiographic criteria for severe MR Definite

a. 2D Echo evidence of disruption of the MV apparatus (papillary muscle rupture, etc.)

b. ERO ≥0.4 cm2

c. MR volume ≥60 ccd. RF ≥55%

e. PV systolic flow reversal

f. MR color flow jet reaching LA posterior wallSuggestive

a. Color flow area ≥40%

b. Eccentric MR jet reaching the LA posterior wall

c. Dense CW-Doppler signald. Increased E velocity (≥1.5 m/s for native valves and 2 m/s for prosthetic valves)

e. LV dimension >7 cm (along with color flow evidence of MR)f. LA size ≥5.5 cm

g. Elevated E/A ratio

Tricuspid Valve DiseaseA. Introduction

a.

Tricuspid stenosisTricuspid stenosis (TS) is a rare clinical condition, with rheumatic disease

accounting for more than 90% of cases. In patients with rheumatic MV

disease, only 3-5% have concurrent TS. Table 34 lists the more unusualcauses of TS.

b. Tricuspid regurgitation

Secondary tricuspid regurgitation (TR) is much more common than primary TR. Functional TR resulting from pulmonary HTN is seen in

patients with significant left-sided heart disease, those with primary

pulmonary HTN, and those with pulmonary disease leading to cor

pulmonale. Functional TR also occurs in patients with RV dilatation asseen with RV infarction or an ASD. TR occurs in as many as 30-50% of

patients with rheumatic mitral valve disease.



83

Table 34. Etiologies of tricuspid valve dysfunction

StenosisRheumatic (>90%)

Isolated stenosisCarcinoid syndrome

Congenital

Other causesActive infective endocarditis with obstructing vegetation

Metabolic or enzymatic disorders (e.g. Whipple’s disease, Fabry’s disease)

Pharmacologic agents (e.g. Methysergide, fenfluramine-phentermine)

Regurgitation Normal valve (Functional TR)

Conditions producing annular dilatation and papillary muscle malalignmentPulmonary HTN of any cause, with RV dilatation

Papillary muscle dysfunction

RV trauma

Acute or remote MI

Infiltrative myocardial disease (e.g. amyloid, sarcoid)

Abnormal valve (Organic TR)Rheumatic

Congenital (mainly Ebstein’s anomaly)

Infective endocarditis (IV drug users)Carcinoid syndrome

Floppy tricuspid valve


The normal TV orifice area is 8 to 12 cm2; significant symptoms and signs of TS

may be seen when the valve area is compromised to ≤2cm2. As with MS the

gradient across the valve is dependent on the diastolic filling period and cardiac

output. Thus, exercise is associated with a significant increase in the gradientacross the valve.

The RA pressure pulse in TS is characterized by an exaggerated a wave (if insinus rhythm). As with MS, there is slowing of the y descent and the absence of

diastasis between the RA and RV pressure pulses (Figure 85). HR influences the

pressure gradient as it does in MS. These effects are subtle though since in mostcases the valve gradient is no more than 5 to 8 mmHg.

Figure 85. RA and RV

pressure tracings in TS. The

transvalvular gradient isshaded. Note the

exaggerated a wave, and the

delayed y descent.



84

As with MV the TV area can be calculated from the planimetered area under the

RV and RV pressure curves using the Gorlin formula (see section on AS for

derivation of this formula):

TVA (cm2 ) = CO ( ml/min )/DFP x HR44.3√ MVG

This method is not always accurate due to low pressure system at the tricuspid

valve. TR is detected, at the time of right heart catheterization, by the presence of

large v waves in the RA pressure pulse; in severe cases of TR, the v wave mayfollow the contour of the RV pressure pulse, although the peak systolic pressure

in RA always remains less than that of RV (Figure 86).

Figure 86. RV

and RA

pressuretracings in a

patient withsevere TR.

In cases of combined TR and TS (Figure 87), there is a diastolic gradient along with the v

wave of the TR.

Figure 87. Simultaneous RV and RA pressure tracings in combined TS and

TR and atrial fibrillation. Note the early

diastolic delay in y descent and the c-v wave during systole. The shaded area

represents the diastolic gradient during

a single beat.

C. Echocardiography

a. Tricuspid stenosis

Echocardiography can be used to determine the cause of TS and the

associated abnormalities (MS in patients with rheumatic disease). 2D

echocardiographic images show thickening and shortening of TV leaflets.Commissural fusion and diastolic bowing indicate rheumatic disease. The



85

normal tricuspid inflow velocity is lower than 0.5 to 1 m/s, with a mean

gradient of <2 mmHg. There is a respiratory variation in TV inflowvelocity. The evaluation of TR by Doppler (Figure 88) is similar to the

method described for MS (use the constant of 190 for PHT method). TS is

considered severe when the mean gradient is ≥7 mmHg and PHT ≥190

ms.

TVA = 190

T 1/2

Figure 88. A. PW Doppler recording of TV inflow from a patient with mild TS. The

peak velocity is 1.7 m/s and rapidly falls to 0 by end diastole. B. CW Doppler recording

from a different patient with more severe TS. Note the increase in the rate of flowacceleration, increased peak velocity (2 m/s) and a slow rate of flow deceleration. (From

Wayman, 1994)

b. Tricuspid regurgitation

Hemodynamically significant TR results in progressive RV and RA

enlargement due to volume overload. RV volume overload is associated

with a pattern of abnormal septal motion seen on M-mode

echocardiography (paradoxical septal motion). On 2D short axis imaging,the interventricular septum appears flattened in diastole. The differential

diagnosis of paradoxical septal motion and RV dilatation includes other

causes of RV volume overload such as ASD, partialanomalous pulmonary venous return, pressure

overload due to Pulmonic valve disease, or pulmonary HTN (either due to left-sided heart

disease or intrinsic lung disease). TR can be

evaluated with Doppler flow techniques in a similarmanner to that described for assessment of MR.

Figure 89. Schematic diagram of color flow mapping for

semiquantitative evaluation of TR severity from the subcostal

window. Severe (4+) TR is associated with systolic reversal in

the hepatic veins. (From Otto, 2000)



86

Color flow mapping allows for assessment of severity. Mild TR is

characterized by localized flow disturbance in systole with less than a 1/3rd

of atrial area. Moderate TR fills between 1/3rd

and 2/3rd

of the RA, whilesevere TR fills more than 2/3

rd of an enlarged RA (Figure 89).

Severe TR results in systolic flow reversal in the IVC and SVC, analogous

to the physical finding of a systolic pulsation in the neck veins. IVC flowis best recorded in the central hepatic vein, which provides a flow channel

parallel to the ultrasound beam from a subcostal approach with no venous

valves between the recording site and the RA (Figure 90).

Figure 90. A. Hepatic vein PW and

CW Doppler showing markedsystolic reversal (arrows) caused by

severe TR. B. Doppler spectrum of

TV in a patient with severe TR.Forward inflow velocity is increased

(E=1.4 m/s) and TR peak velocity isrelatively decreased because of a

small pressure gradient between theRV and the RA. A large v wave

makes the Doppler spectrum dented

during mid to late systole

(arrowheads). C. In comparison, CW

Doppler velocity spectrum from a patient with pulmonary HTN and

moderate TR shows increased peak

velocity but with a roundedconfiguration. (From Oh, 1999)

The absolute value maximum velocity in TR CW Doppler

recording reflects the maximum pressure difference acrossthe TV and not the severity of regurgitation. Severe

regurgitation with a normal RVSP (as seen with TV

endocarditis) has a low maximum velocity. Mild TR in the

presence of pulmonary HTN (as seen in PPHTN) has a highmaximum velocity. However, the intensity of CW signals,

relative to the antegrade flow signal intensity does not

relate to TR severity. In addition the shape of velocity-timecurves indicates the time course of instantaneous pressure

differences across the valve (Figure 91). A RA v waveseen in acute TR, results in a more rapid decline in velocityin late systole similar to that seen in acute MR. Table 35

lists the echocardiographic criteria for severe TR.

Figure 91. Continuous-wave Doppler recording of TR in a patient withchronic (above) and acute (below) TR. Note the late systolic velocity

decline (v wave) in the acute case (arrow). (From Otto, 2000)

A



87

Table 35. Echocardiographic criteria suggesting severe TR:

Color flow regurgitation jet area ≥30% of RA areaDense CW Doppler signalAnnulus dilatation (≥4cm) or inadequate cusp coaptation

Late systolic concave configuration of CW signal

Increased tricuspid inflow velocity (≥1.0 m/s)Systolic flow reversal in hepatic vein

Pulmonic Valve DiseaseA. Introduction

In patients with pulmonic valve disease it is important to distinguish primary

valve abnormalities (such as congenital) from valve dysfunction caused by

pulmonary hypertension.

a. Pulmonary stenosis

PS is congenital in 95% of cases; rare causes include carcinoid syndrome

and rheumatic valve disease. Although PS can be a feature of other typesof congenital heart disease (e.g. tetralogy of Fallot), 80% of cases are

isolated PS. The abnormal valve is classified as unicommissural (with prominent systolic doming of leaflets and eccentric orifice), bicuspid (with

fused commissures), or dysplastic (severely thickened and deformed

leaflets). Rarely, PS can be associated with the aneurysm of the PA.

b. Pulmonary regurgitation

Pathologic PR is rare in adults, although a small amount of PR isdetectable by Doppler in most normal individuals. Pathologic PR is

distinguished by a longer duration of flow (typically holodiastolic) and a

wider jet as the regurgitant flow crosses the valve. PR in adults is most

often caused by PA and annular dilatation secondary to pulmonary HTN.Other causes are listed in Table 36. PR may also be the result of prior

surgical interventions for congenital heart disease.



88

Table 36. Etiologies of Pulmonic valve dysfunction

StenosisCongenital (>95%)

IsolatedWith other abnormalities (e.g. Tetralogy of Fallot)

Acquired

Carcinoid syndromeRheumatic

Infective endocarditis with obstructing vegetation

Regurgitation Normal valve

Dilatation of Pulmonic trunk and annulus

Pulmonary arterial HTN of any cause

Idiopathic pulmonary trunk dilatationMarfan syndrome

Abnormal valve

Congenital

Carcinoid syndromeInfective endocarditis, with perforation or retraction

Catheter trauma (Balloon dilatation)

External blunt trauma

RheumaticRheumatoid arthritis and syphilis

Pharmacologic agents (Fenfluramine-phentermine)



Moderate to severe obstruction of the PV places a pressure overload on the

RV that, in turn, leads to significant RVH. The pressure tracings from RVand PA (Figure 92) can be used to calculate the mean gradient similar tothe method used for AS. Pulmonic valve area can also be calculated by

the Gorlin formula as follows:

PVA (cm2 ) = CO ( ml/min )/SEP x HR

44.3√ MVG

Where MVG is the mean valve gradient calculated from the pressuretracings of RV and PA. This method however has not been validated

hence is not commonly used.



89

Figure 92.

Simultaneous pressurerecordings from RV,

PA, and RA in a patient

with Pulmonic Stenosis.The shaded area is the

Pulmonic Stenosis

gradient.


The basic cardiac defect in PR is retrograde leakage of blood from themain PA into RV during diastole (Figure 93). Unless the PADP is

severely elevated, the driving force between the PA and RV is not large,and the regurgitant fraction of the stroke volume remains relatively small.Moreover RV can tolerate a relatively large volume overload, and thus,

the patient with PR commonly exhibits no impairment of CO either at rest

or during exercise. Also, the RVEDP and RAP are not elevated unless

there is an associated pressure overload on RV, or PR is long-standing.

Figure 93. Simultaneous RVand PA pressure

recordings from a

patient with PR.

C. Echocardiography


The echocardiographic study of valvular PS should include:(a) The morphology of the stenotic pulmonic valve

Morphologically the valve can be unicuspid (acommissural orunicommissural), bicuspid (usually seen in association with tetralogyof Fallot), tricuspid and quadracuspid.

(b) The diameter of pulmonary annulus

In isolated pulmonic valve stenosis, the pulmonary annulus is usuallynormal in size but can also be hypoplastic.

(c) The size of the RV

The RV is usually concentrically hypertrophied. Infundibular

hypertrophy can result in subvalvar obstruction (seen in close to 1/3rd



90

of valvular PS). Size of the RV can be assessed from parasternal long-

axis view tilted towards the RV inflow, from short-axis view, and fromapical four-chamber and subcostal four-chamber and short-axis view.

(d) The degree of dilatation of the PA

Isolated PS is almost always associated with Poststenotic dilatation of

the PA, which can extend to the proximal portion of the left branch.This is the result of high velocity flow across the stenotic valve

impacting on the arterial wall. The degree of Poststenotic dilatation is

not related to the severity of PS. The dilatation is best seen from parasternal long-axis view of the RVOT and also from short-axis view.

(e) The severity of the obstruction

Maximal velocities are recorded using CW-Doppler. Peak and meangradients are calculated from the velocities using the simplified

Bernoulli equation. Color flow Doppler mapping of the RVOT should

be done prior to CW interrogation to guide sample line positioning.The RVOT should be interrogated with PW Doppler to establish

presence of any infundibular stenosis. If the velocities proximal to thePV are >1 m/s, the expanded Bernoulli equation should be used tominimize the errors in predicting the peak gradient.

(f) Associated anomalies.

It is unusual to find other anomalies with PS and an intact ventricular

septum. However when present PFO and ASD (secundum) are themost common.

Echocardiographically, PS is characterized by (1) systolic doming of thestenotic leaflets into the pulmonary artery (Figure 89), (2) abnormal initial

systolic leaflet motion, (3) opening or doming following atrial systole but before ventricular systole in more severe cases, and (4) measurements of

peak flow velocity and pressure gradient using CW Doppler (Figure 95).

Poststenotic PA dilatation may be present and should be sought for.Differentiation of valvular PS from subvalvular or supravalvular

obstruction can be difficult by 2D echo. Careful interrogation with PW

Doppler should be used to better delineate the nature of the obstruction.In patients with relatively normal cardiac

output, classification of PS is routinely

based on measurements of RV pressure and

valve gradient. Mild stenosis ischaracterized by a RV pressure less than ½

of LV pressure or a valve gradient of <35-40

mm Hg.

Figure 94. Parasternal short-axis view of a stenotic pulmonic valve. Note the doming of the valve in

systole and the thickened, redundant tissue in

diastole. The annular size can also be measured from

this view. (From Valdes-Cruz, 1999).



91

In moderate stenosis, the RV pressure is greater

than 50% but less than 75% of LV pressure, or agradient of >40 mm Hg. Severe PS is defined

as a RV pressure equal or greater than 75% of

the LV pressure or a gradient >60-70 mm Hg.

Decreased RV compliance is further evidenced by elevated RVEDP at rest and abnormal

increased with exercise.

Figure 95. CW Doppler recording in a patient with PS

with a maximum velocity of 2.4 m/s corresponding to a

maximum pressure gradient of 24 mmHg. (From Otto,

2000)


PR is primarily detected by Doppler. It should be noted that PR can be

physiologic and is detected in 92% of normal individuals. The Doppler

diagnosis is based on the demonstration of regurgitant flow in the pulmonary artery (PA) and RVOT by PW or color Doppler demonstration

of regurgitant flow. Color Doppler is better suited to assess jet size and

spatial orientation; PW to assess temporal characteristics; and CW todetermine maximal jet velocity in patients with PHTN. The intensity and

the shape of the CW Doppler velocity-time spectral output provide means

for assessment of PR severity, analogous to the findings in AR.Holodiastolic flow reversal may be noted in the main PA when significant

regurgitation is present (must be distinguished from flow reversal seen in

PDA). Spectral Doppler recording of regurgitant jet velocities permitsestimation of its severity by the intensity of the signal itself as well as the

slope of the deceleration curve (Figure 96). The more severe the

regurgitation, the sharper the deceleration slope since the PADP

approached RVEDP faster.

Figure 96. Short-axis view of the RVOT,

demonstrating the remnant of the pulmonic

leaflets (arrows) in isolated absence of PV.

Doppler recording of velocities across the

pulmonary annulus exhibit low velocity forwardand reverse flow, indicating wide open

regurgitation (From Valdes-Cruz, 1999).

In patients with significant PR, the M-mode and 2D echocardiograms

show evidence of RV volume overload (dilated RV with vigorous



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ejection, paradoxical septal motion). Also vigorous pulsations of the main

PA and its branches are seen (especially in suprasternal views ifaccessible).

When PR is present (even mild), the velocity in PR Doppler profile

reflects the PA to RV diastolic pressure difference (Figure 97). The

instantaneous end-diastolic PA to RV gradient (calculated by modifiedBernoulli equation, 4v2) can be added to an estimate of RV diastolic

pressure (from IVC size and respiratory variation) to provide an estimate

of PA diastolic pressure.

PA diastolic pressure = 4v PR2 + RA pressure

Figure 97. Diagram of

CW Doppler interrogation

of PR from the left

parasternal window andthe PR Doppler spectrum.

For example if the end-

diastolic PR velocity is 3m/s, the end-diastolic PAP

= (4 x 32) + 20 = 56 mm

Hg, assuming an RAP of20 mm Hg (Oh, 2000).

Pulmonary Hypertension

A. Introduction

The normal PAP for a person living at sea level has a peak systolic value of 18 to 25

mmHg, a peak end-diastolic value of 6 to 10 mmHg, and a mean PAP value of 12 to 16

mmHg. The normal mean pulmonary venous pressure is 6 to 10 mmHg, therefore themean AV pressure difference, which moves the entire cardiac output across the

pulmonary vasculature, ranges from 2 to 10 mmHg (compared to a mean of 90 mmHg

required to move the same cardiac output across the systemic vascular bed). Thus, thenormal pulmonary vascular bed offers close to 1/10

th the resistance to flow offered by the

systemic bed. Vascular resistance is generally quantified, by analogy to Ohm’s law, as

the ratio of pressure drop (DP in mm Hg) to mean flow (Q in liters/min). The ratio iscommonly multiplied by 79.9 (or 80 for simplification) to express the results in dynes-

seconds-centimeters –5

. This conversion to metric units may be avoided, i.e., resistance

may be expressed in units of mm Hg/liter/min, which is referred to Wood units (after the

English cardiologist Paul Wood). The calculated pulmonary vascular resistance in normaladults is 67 ± 23 dynes-sec-cm

–5, or 1 Wood unit. Vascular resistance reflects a

composite of variables that includes (but is not limited to) the cross-sectional area of

small muscular arteries and arterioles, blood viscosity, the total mass of lung tissue (i.e.,resistance is higher in infants and children than in adults), proximal vascular obstruction



93

(e.g., pulmonary coarctation, pulmonary embolism, peripheral pulmonic stenosis), and

extramural compression of vessels (perivascular edema). Hemodynamically pulmonaryHTN is defined as systolic pulmonary pressures >35 mmHg, diastolic pressure >15

mmHg, and mean PAP >25 mmHg.

Table 37. Etiologic classification of pulmonary HTNPulmonary venous HTN

Thoracic Aorta (CoA, Supravalvular AS)

LV (AS or AI, HOCM, Constrictive pericarditis)

LA (Myxoma, MS, Cor triatriatum)Pulmonary veins (Congenital PV stenosis, Mediastinitis or fibrosis, neoplasms)

Chronic hypoxia

High altitudeInadequate respiratory excursion (Obesisty, kyphoscoliosis, neuromuscular disease)

Chronic upper airway obstruction

Chronic lower airway obstruction (Bronchiectasis, Chronic bronchitis, Cystic fibrosis)

Chronic diffuse pulmonary parenchymal diseaseInterstitial fibrosis

PneumoconiosesGarnulomatous disease (e.g. sarcoidosis)

Connective tissue disease (e.g. RA, SLE, Scleroderma)

Vascular disorders of the lungPrimary vascular disease

Plexogenic pulmonary arteriopathy (e.g. AIDS, diet pills)

Connective tissue diseaseThrombotic diseases (Sickel cell disease, Pulmonary veno-occlusive disease)

Embolic disease (pulmonary emboli, tumor emboli, Schistosomiasis)

Left-to-right shunts

Extracardiac shunts (PDA, Aortopulmonary window)Intracardiac shunts (VSD, ASD, AVSD)

Various causes of pulmonary HTN are listed in table 37 according to the pathophysiologic mechanism.


Right heart catheterization is used to assess RVEDP, PAP, and PCWP in patients

with pulmonary HTN. Pulmonary angiography is usually undertaken at the same

time. Pulmonary angiography often represents the final step in assessing a patientwith pulmonary HTN. Delineation of precapillary causes of pulmonary HTN is

the primary goal of this procedure. Postcapillary causes, such as long-standing

pulmonary venous HTN (e.g. MS, LV failure), or other pulmonary vasculardisorders, such as those associated with venous occlusion, generally present

clinical and laboratory features that provide the diagnosis. However, left heartcatheterization, coronary angiography, regional PCWP determinations, andretrograde pulmonary venography may be required to confirm or exclude these

diagnoses. Consequently, the usual goal of pulmonary angiography in the patient

with pulmonary HTN is to define the prearteriolar anatomy to distinguish between

major vessel (main, lobar, and segmental) and small vessel disease.



94

C. Echocardiography

Determination of PAP is routine part of echocardiographic examination. Severalapproaches have been suggested for non-invasive estimation of PAP including (1)

Doppler derived gradients, (2) changes in PV motion and PA flow profiles, and

(3) measurement of RV IVRT. At least one measure of PAP can be obtained in

up to 98% of patients.

a. Doppler derived gradients

PAP can be estimated from (1) RV-RA pressure gradient in patients withTR, (2) LV-RV pressure gradient in patients with VSD, (3) the aorta-PA

gradient in patients with aortopulmonary connections (e.g. PDA), and (4)

from the PA-RV gradient in patients with PR. The most commonapproach is to estimate PASP from RV pressure (assuming there is no PS)

determined as the sum of RV-RA pressure gradient and either an assumed

or clinically determined RAP (Figure 98).

Figure 98. A. Diagram demonstrating measurement of RV pressure from TR velocity. The peak RVSP is

estimated by adding RAP to the pressure gradient derived from TR velocity (4 x (peak TR velocity)2) B.

Simultaneous RA and RV pressure tracings and TR velocity recording by CW Doppler echocardiography

(Oh, 2000).

RAP is best estimated from evaluation of IVC during respiration. From asubcostal window this segment of IVC is imaged during quiet respiration

(M-mode can be used for accurate measurements). If the IVC diameter isnormal (1.2 to 2.3 cm) and the segment next to RA collapses at least 50%during respiration, then RAP is equal to normal intrathoracic pressure (i.e.

5-10 mmHg). Failure to collapse with respiration and/or dilatation of IVC

and hepatic veins is associated with higher RAP (Table 38).



95

Table 38. Estimation of RA pressure

IVC Changes with respiration or Sniff Estimated RAP

Small (<1.5 cm) Collapse 0-5 mmHg

Normal (1.5-2.5 cm) Decreased by >50% 5-10 mmHg

Normal Decreased by <50% 10-15 mmHg

Dilated (>2.5 cm) Decrease by <50% 15-20 mmHg

Dilated with dilated hepatic veins No change >20 mmHg

In patients with VSD, the RVSP can be determined as the peak aortic

pressure (measured by a sphygmomanometer), which is equal to the LV

systolic pressure minus the gradient across the defect.

RVSP = SBP – 4vVSD2

With associated PS, the PAP will equal the RV pressure minus the

transpulmonary gradient. When a VSD and PS coexist, the combined

calculated pressure differences may exceed the true gradient between the

LV and PA by 10-15 mmHg, because the velocity peaks can occur atdifferent points in systole.When there is a direct systemic to PA connection (e.g. PDA, BT shunt),

the PAP will equal the systemic cuff pressure minus the gradient.

RVSP = SBP – 4v shunt 2

Finally in a patient with PR, the maximal velocity in the regurgitant jet

approximates the diastolic pressure in the PA except when the RVdiastolic pressure is elevated.

PAP (end-diastolic) = 4v PRend-diastolic2

+ RAP

A characteristic pattern in hepatic venous flow is seen in patients with

pulmonary HTN (Figure 99). There is a prominent atrial flow reversal in

hepatic vein caused by increased diastolic pressure and decreasedcompliance of RV.

Figure 99. PW Dopplerrecording of hepatic vein

velocities in pulmonary HTN.

There is a prominent atrial flow

reversal (arrows). D, diastolic; S,systolic.



96

b. Other findings (M-mode and 2-D)

Pulmonary HTN is recognized when the following M-mode and 2Dechocardiographic features are present:

1. Diminished or absent a (atrial) wave of pulmonary valve seen on

M-mode. The degree of a wave dips correlates with severity of

PHTN.2. Mid systolic closure or notching of PV

3. Enlarged chambers on the right side of the heart

4. D-shaped LV cavity caused by flattened LV septum. This iscaused by RV pressure overload (Figure 100).

Figure 100. Parasternal short-axis view of adilated RV compressing the LV. Note the

posterior bulging of the IVS in systole (From

Valdes-Cruz, 1999).

These features though are onlyqualitative.

c. RV isovolumetric relaxation time

Pulmonary HTN is associated with prolongation of the RV IVRT. This

time can be measured as the interval between PV closure and TV opening,recorded either in M-mode or via Doppler (closure clicks). In adults, this

approach is rarely used because of difficulty recording PV closure given

the suboptimal studies in many patients.The RVOT flow velocity has a characteristic pattern as PAP increases

(Figure 101 and 102). The acceleration phase becomes shorter with

increased PAP. Mahan’s equation can be used to estimate mean PAP:

MPAP = 79 – 0.45 (AcT)

Where AcT is the acceleration time in msec (normal AcT ≥120 msec) and

MPAP is the mean pulmonary artery pressure. Acceleration time isdependent on CO and HR. Multiple studies have shown that an AcT <100

ms has a strong correlation with PAP > 20 mm Hg.



97

Figure 101. RVOT flow velocity profile (PW

Doppler) showing measurements used to calculatemean PAP (MPAP). AcT, acceleration time; IVRT,

isovolumetric relaxation time.

Figure 102. Spectral Doppler velocity

waveform of the PA in PHTN. Note the rapid

acceleration time (45 msec) and the notching(arrow) of the systolic curve (W pattern) due to

decreased flow in mid systole (From Valdes-

Cruz, 1999).

The ratio of AcT and RV ejection time(ET) can also be used to assess severity

of PHTN. It is generally agreed that

patients without PHTN have a AcT/ETratio >0.36.

Intracardiac ShuntsA. Introduction

Normally, pulmonary blood flow and systemic blood flow are equal. Whenthere is an abnormal communication between intracardiac chambers or great

vessels, blood flow is shunted either from the systemic circulation to the

pulmonary circulation (left-to-right shunt), from the pulmonary circulation tothe systemic circulation (right-to-left shunt), or in both directions

(bidirectional shunt). Although many shunts are suspected before cardiaccatheterization, unexpected findings during catheterization should trigger athorough search for the cause. For example, an unexplained pulmonary artery

oxygen saturation exceeding 80% should raise suspicion of a left-to-right

shunt, whereas unexplained arterial desaturation (<95%) may indicate a right-to-left shunt. Arterial desaturation commonly results from alveolar

hypoventilation and associated physiological shunting, the causes of which

may include oversedation from premedication, pulmonary disease, pulmonary

venous congestion, pulmonary edema, and cardiogenic shock. Persistence of

RVOT PW

AcT IVRT



98

arterial desaturation after administration of 100% oxygen should raise a

suspicion of a right-to-left shunt. Noninvasive methods for the detection ofintracardiac shunts include echocardiographic, radionuclide, and magnetic

resonance imaging techniques.

B.

Cardiac Catheterizationa. Oximetric method:

The oximetric method is based on blood sampling from various cardiac

chambers for oxygen saturation determination. A left-to-right shunt is detectedwhen there is a significant increase in blood oxygen saturation between two

right-sided vessels or chambers (step up). A screening oxygen saturation

measurement for any left-to-right shunt should be performed with every rightheart catheterization by sampling blood in the superior vena cava (SVC) and

the pulmonary artery (PA). If the difference in oxygen saturation between

these samples is ≥8%, a left-to-right shunt may be present, and a full oximetryrun should be performed. This includes obtaining blood samples from the

superior vena cava (SVC), inferior vena cava (IVC), right atrium, rightventricle, and pulmonary artery. In cases of ASD or VSD, it may be helpful toobtain multiple samples from the high, middle, and low right atrium or the

right ventricular inflow tract, apex, and outflow tract in order to localize the

level of the shunt. One may miss a small left-to-right shunt using the right

atrium for screening purposes rather than the SVC because of incompletemixing of blood in the right atrium, which receives blood from the IVC, SVC,

and coronary sinus. Oxygen saturation in the IVC is higher than in the SVC

because the kidneys use less oxygen relative to their blood flow than do otherorgans, while coronary sinus blood has very low oxygen saturation. Mixed

venous saturation is most accurately measured in the pulmonary artery aftercomplete mixing has occurred.

A full saturation run involves obtaining samples from the high and low IVC;

high and low SVC; high, mid, and low right atrium; right ventricular inflow,outflow tracts, and mid-cavity; main pulmonary artery; left or right pulmonary

artery; pulmonary vein and left atrium if possible; left ventricle; and distal

aorta. When a right-to-left shunt must be localized, oxygen saturation samplesmust be taken from the pulmonary veins, left atrium, left ventricle, and aorta.

Despite its lack of sensitivity, clinically significant shunts are generally

detected by this technique. Another method uses a balloon-tipped fiberoptic

catheter that allows for continuous registration of oxygen saturation as it iswithdrawn from the pulmonary artery through the right heart chambers into

the SVC and IVC.

The principles used to determine Fick cardiac output are also used to quantifyintracardiac shunts. To determine the size of a left-to-right shunt, pulmonary

blood flow and systemic blood flow determinations are required. Pulmonary

blood flow (PBF) is simply oxygen consumption divided by the difference inoxygen content across the pulmonary bed, while systemic blood flow (SBF) is

oxygen consumption divided by the difference in oxygen content across the

systemic bed. The effective blood flow (EBF) is the fraction of mixed venousreturn received by the lungs without contamination by the shunt flow. In the



99

absence of a shunt, PBF, SBF, and EBF are all equal. These equations are

shown below:

PBF = O2 consumption (ml/min)

(PVO2 – PAO2 )

SBF = O2 consumption (ml/min)(SAO2 – MVO2 )

EBF = O2 consumption (ml/min)(PVO2 – MVO2)

Where PVO2, PAO2, SAO2, and MVO2 are the oxygen contents (in millilitersof oxygen per liter of blood) of pulmonary venous, pulmonary arterial,

systemic arterial, and mixed venous bloods, respectively. The oxygen content

is determined as outlined in the section on Fick cardiac output and iscalculated by:

O2 conent = O2 saturation x O2 carrying capacity (1.36 ml/gm) x Hgb Concentartion (gm/L)

Systemic arterial oxygen content may be substituted, assuming systemic

arterial saturation is 95% or more. As discussed above, if systemic arterialsaturation is less than 95%, a right-to-left shunt may be present. If arterial

desaturation is present but not secondary to a right-to-left shunt, systemic

arterial oxygen content is used. If a right-to-left shunt is present, pulmonaryvenous oxygen content is calculated as 98% of the oxygen capacity.

The mixed venous oxygen content is the average oxygen content of the blood

in the chamber proximal to the shunt. When assessing a left-to-right shunt atthe level of the right atrium, one must calculate mixed venous oxygen content

on the basis of the contributing blood flow from the IVC, SVC, and coronary

sinus. The most common formula used is the Flamm formula:

MVO2 = 3(SVC O2 content) + (IVC O2 content)4

The difference between the SVC and the IVC O2 content is due to loweroxygen extraction of the kidneys. Assuming conservation of mass, the size of

a left-to-right shunt, when there is no associated right-to-left shunt, is simply:

L → R shunt = PBF – SBF (Or Q p – Q s )

When there is evidence of a right-to-left shunt in addition to a left-to-rightshunt, the approximate left to right shunt size is:

L → R shunt = PBF – EBF (or Q p – Q EP )

While the approximate right-to-left shunt size is:



100

R → L shunt = SBF – EBF (or Q s – Q EP )

The flow ratio PBF/SBF (or QP/QS) is used clinically to determine the

significance of the shunt. A ratio of less than 1.5 indicates a small left-to-right

shunt. A ratio of 2.0 or more indicates a large left-to-right shunt and generally

requires repair in order to prevent future pulmonary and/or right ventricularcomplications. A flow ratio of less than 1.0 indicates a net right-to-left shunt.

If oxygen consumption is not measured, the flow ratio may be calculated asfollows:

Qp = SAO2 – MVO2

Qs PVO2 – PAO2

Figure 103. Schematic diagram of blood oxygenation in the heart in presence of a relatively large ASD

with L to R shunting and a normal PVR. Numbers in the diagram indicate Oxygen content in differentchambers calculated from O2 saturations measured at the time of cardiac catheterization. (From Peterson,

1997)

Figure 104. Schematic diagram of blood oxygenation in the presence of a relatively large VSD and normal

PVR. (From Peterson, 1997)



101

Figure 105. Schematic diagram of blood oxygenation in the heart in the presence of PDA and normal

PVR. (From Peterson, 1997)

Figure 106. Schematic diagram of blood oxygenation in a heart with tetralogy of Fallot and bidirectionalshunting at the high ventricular septal level. L to R shunting is relatively small owing to obstruction to

pulmonary vascular bed by pulmonary stenosis. R to L shunting is facilitated by aortic override to

ventricular septum. (From Peterson, 1997)

Figures 103 to 106 are different examples of both intra and extra-cardiac

shunts and calculation of Q p/Qs.

b. Indicator dilution method

While the indicator-dilution method is more sensitive than the oximetric

method in detection of small shunts, it cannot be used to localize the level of a

left-to-right shunt (Figure 107). An indicator such as indocyanine green dye

is injected into a proximal chamber while a sample is taken from a distalchamber using a densitometer and the density of dye is displayed over time. In

order to detect a left-to-right shunt, dye is injected into the pulmonary arteryand sampling is performed in a systemic artery. Presence of a shunt is

indicated by early recirculation of the dye on the down slope of the curve. The

presence of aortic or mitral regurgitation may distort the downslope of the

curve, thereby yielding a false positive result. In adults, the indocyanine greenmethod provides estimates of shunt magnitude that are somewhat smaller than



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those of the oximetric method, although they are in general agreement with

one another concerning the Q p/Qs. In order to detect a right-to-left shunt, dyeis injected into the right heart proximal to the presumed shunt and sampling is

performed in a systemic artery. If there is a right-to-left shunt, a distinctive

early peak is seen on the upslope of the curve. The level of the right-to-left

shunt may be localized by injecting more distally until the early peakdisappears. Shunts may also be quantified using this technique.

Figure 107. Indicator dilution curves for shunts. L→ R shunts (increased pulmonic flow). Indicator is notcleared rapidly but recirculates through central circulation via defect. Based on the magnitude of the shunt,

a constant fraction leaves the central pool with each circulation. R→ L shunt (decreased pulmonic flow). A

portion of the indicator passes directly to the arterial circulation via the defect without passing through thelungs and arrives at the arterial sampling site before the portion that did traverse the pulmonary circulation.

(From Kern, 1999)

C. Echocardiography

With PW Doppler or color flow imaging, a flow disturbance is found

downstream from the defect: on the right side of the IVS for the VSD, in the

RA for ASD, and in PA for a PDA. Similar to a stenotic or regurgitantorifice, the velocity of blood flow through the shunt orifice is related to the

pressure gradient across the defect.A L to R intracardiac shunt imposes a chronic volume overload on the

receiving chamber with consequent dilatation of the affected chamber. With

ASD both RA and RV dilate and paradoxical septal motion is seen. With a

PDA, the volume overload is imposed on LA and LV. Although it mightseem that a VSD would cause RV volume overload, in fact RV size usually is

normal since the LV effectively ejects the shunt flow across the defect directlyinto the PA in systole. Instead, LA and LV dilatation are seen, since these

chambers receive the increased pulmonary blood flow as it returns to the left

side via the pulmonary veins.The Q p/Qs can be calculated by Doppler echocardiographic measurements of

SV at two intracardiac sites (Figure 108). In the case of an ASD,



103

transpulmonic flow (Q p) is calculated from PA CSA and velocity-time integral

(VTI), while systemic flow (Qs) is calculated from measurements of LVOTCSA and VTI.

Figure 108. Schematic diagram of Doppler echo calculation of Q p/Qs ratio. Q p is calculatedfrom transpulmonic SV using PA diameter measured at the site of Doppler sample position

and the VTI of the PA flow. A circular CSA is assumed. Similarly Qs is calculated from

LVOT diameter and VTI. (From Otto, 2000)

Q p and Qs are calculated as follows:

Qp = CSA PA x VTI PA

Qs = CSA LVOT x VTI LVOT

Q p = ___CSA PA x VTI PA ___

Q s CSA LVOT x VTI LVOT

This approach is fairly accurate when high quality 2D images are obtained

for precise measurements of the diameters (LVOT and PA) and whenDoppler velocities are recorded at a parallel intercept angle to flow.

D.

Man-made shunts and palliative procedures

First surgical treatment for congenital heart disease was ligation of patent-

ductus arteriosus by Robert Gross in 1938. Subsequently in 1944 successfulrepair of coarctation of aorta was performed by Clarence Crafoord. First

palliative procedure was the creation of arterial to pulmonary shunt in patient

with tetralogy of Fallot by Alfred Blalock in 1944 (Blalock-Taussig shunt).

Since the early days of surgical treatment for congenital heart disease many



104

different palliative and corrective procedures have come and gone. Table 39

lists some of the more common of these.

Table 39. Palliative and corrective procedures in congenital heart disease

Procedure Description

Systemic Venous-to-pulmonary artery shuntsClassic Glenn SVC to RPA

Bidirectional Glenn SVC to RPA and LPA

Bilateral Glenn RSVC and LSVC to RPA and LPA

Fontan RA to main PA

Systemic arterial-to-pulmonary artery shunts

Classic Blalock-Taussig Subclavian artery to RPA

Modified Blalcok-Taussig Subclavian artery to ipsilateral PA (prosthetic graft)

Potts’ anastemosis Descending aorta to LPA

Waterston shunt Ascending aorta to RPA

Palliative and corrective procedures

Mustard Atrial switch operation (TGA). The baffle is made

from autologous pericardial tissue (after resection of

interatrial septum) and rarely from syntheticmaterial

Senning Atrial switch operation (TGA). The atrial baffle is

fashioned in situ using tissue from RA wall and

interatrial septum

Rastelli For patients with TGA, VSD and PS/subpulmonary

stenosis. Redirecting of blood at the ventricular

level with LV tunneled to the aorta through theVSD and a valved conduit placed from RV to PA

Jatene Arterial switch operation

Norwood First stage of procedure for hypoplastic left-heart

syndrome. Creating and unobstructed

communication between RV and the aorta and

enlargement of the ascending aorta

Hypertrophic Cardiomyopathy (HCM)

A. Introduction

Hypertrophic cardiomyopathy (HCM) is a genetic disease with autosomal

dominant inheritance pattern. Its prevalence in general population is0.2%. It is characterized by hypertrophy of left ventricle, with markedly

variable clinical manifestations and genetic, morphological and

hemodynamic abnormalities. Over 70 individual disease- causing

mutations affecting the four genes encoding the cardiac sarcomere have

been reported. These are the β-myosin heavy chain on chromosome 14 (~40%); cardiac Troponin T on chromosome 1(10-20%); α-tropomyosin on

chromosome 15 (5%); and myosin-binding protein C on chromosome 11(15%).

In HCM, the distribution of hypertrophy is almost always asymmetrical,

but there is substantial structural diversity, and no particular phenotypicexpression of HCM can be regarded as “classic” or typical of the overall

disease. Absolute LV wall thickness in clinically identified patients range



105

broadly from mildly increased (13-15 mm) to massively increased (>30

mm). Virtually all possible patterns of LV wall thickening occur, but theanterior ventricular septum is usually the predominant region of

hypertrophy.

B.

Cardiac Catheterizationa. Gradients

Cardiac catheterization in these patients shows a decrease in LV

compliance and in some patients a systolic pressure gradient withinthe body of the LV, which is separated from a subaortic chamber

by a thickened septum and the anterior mitral valve leaflet.

Figure 109. Simultaneous LV and

Aortic pressure

tracings in a patientwith HOCM showing

the dynamic nature ofthe LVOT

obstruction. Note the

increase in gradient

with amyl nitrate(From Braunwald,

1995).

The pressure gradient might be quite labile and vary between 0 and175 mmHg in the same patient under different conditions. The arterial

pressure tracing may demonstrate a “spike and dome” configuration

similar to the carotid pulse tracing (Figure 109). Due to the decreasedLV compliance, the mean LA (and particularly a wave), and the

LVEDP are usually elevated. A pressure gradient across the RVOT

occurs in approximately 15% of the cases who have obstruction to the

LV outflow and appears to be due to markedly hypertrophied RVtissue.



106

Figure 110. Brockenbrough phenomenon. In a patient with HOCM the post extra-

systolic beat demonstrates an increased gradient, resulting in decreased aortic

pressure (Ao) even though LV systolic pressure has increased significantly. This

feature is characteristic of dynamic LVOT obstruction. In fixed obstruction like AS,

the gradient should not change significantly and the aortic pulse pressure shouldremain the same or increase slightly.

A

f

e

at

ur e

t

ha

t

is characteristic to HCM is the variability and the lability of the LVOT

gradient. Three basic mechanisms are involved in the production ofdynamic gradients (Table 40), all of which act by reducing ventricular

volume and presumably heighten the apposition of the anterior mitral

valve leaflet against the septum: (1) increased contractility; (2)decreased preload; and (3) decreased afterload.

Table 40. Effects of interventions on outflow gradient and systolic murmur in HCMContractility Preload Afterload

Increases in murmur and gradient

Valsalva (strain phase) - ↓ ↓

Standing - ↓ -

postextrasystole ↑ ↑ -

Amyl nitrate - then ↑ ↓ then ↑ ↓ Tachycardia ↑ ↓ -

Exercise ↑ ↑ ↑

Hypovolemia ↑ ↓ ↓

Decreases in murmur and gradient

Valsalva (overshoot) - ↑ ↑

Squatting - ↑ ↑

Isometric handgrip - - ↑

phenylephrine - - ↑

β-blockade ↓ ↑ -

Post extra-systolic beat



107

b. Percutaneous transluminal septal myocardial ablation (PTSMA)

PTSMA using alcohol induced septal branch occlusion aims to

directly reduce the hypertrophied interventricular septum with a

subsequent expansion of LVOT and a reduction in LVOT gradient.

This is achieved by infarction of the area supplied by the occludedseptal branch.

Current indications are presence of a dynamic LVOT gradient (>30mmHg at rest and >100 mmHg with provocation), and

symptomatic patients (NYHA >III) despite medical therapy.

Patients who have had a previous myectomy or DDD pacing but

continue to have symptomatic disease may also be treated withPTSMA.

After determination of gradients by conventional cardiac

catheterization techniques, coronary angiography is done. Leftcoronary angiography identifies the septal branches (best view is

LAO with caudocranial angulation). The first septal perforator isusually the target for PTSMA. Some centers use myocardialcontrast echocardiography (after selective contrast injections into

septal branches) to identify the target septal branch. After

identification of the target septal branch, up to 5 mls of alcohol is

administered selectively in 1 ml aliquots. After final angiographicdemonstration of septal branch occlusion (Figure 111),

hemodynamic measurements are repeated and new gradient

calculated (Figure 112).

Figure 111. Left coronary angiography showing septal branches (arrows). (A) Initial appearance, (B) finalappearance after alcohol-induced septal branch occlusion (From Topol, 1999)

The procedural success rate without major complications has been

reported between 90 to 97%, with an average reduction in theLVOT gradient of Almost 50 mmHg. Based on number of studies

the complication rates are shown in table 41.



108

Table 41. Complications of PTSMAComplication Rate of occurrence

Death 0 to 5%

Permanent pacemaker implantation 5 to 12%

Temporary pacemaker 30 to 50%

Figure 112. Optimal acute

results after PTSMA, with

complete elimination ofLVOT gradient after

alcohol-induced occlusion

of the septal branch.

This technique is stillrelatively new and is

undergoing both shortand long-term studies.

Obviously as more

and more proceduresare done the complications rates drop and better definition of

indications and contraindications will become available.

C. Echocardiography

Although the most common morphological pattern is that of asymmetric

septal hypertrophy, HCM can present with free wall LV hypertrophy,concentric, or apical hypertrophy. Dynamic LVOT obstruction is the

diagnostic feature of obstructive variant of HCM. This occurs as a result

of bulging hypertrophy of the basal septum narrowing the LVOT. Thevelocity of blood across the LVOT increases producing a Venturi effect.

Due to this the anterior mitral valve leaflet and support apparatus are

drawn up towards the septum (systolic anterior motion, SAM), obstructing

the LVOT. This obstruction is dynamic and depends on the loadingconditions, contractility, and LV size. As a result of the obstruction at the

LVOT, the aortic valve shows a premature midsystolic closure. The other

effect of SAM is the development of MR.



109

a. M-mode/2D

Using M-mode one can document presence of asymmetrichypertrophy, midsystolic AV closure and SAM of the mitral

valve (Figure 113).

Figure 113. A: M-mode echocardiogram showing systolic anterior motion (SAM, double arrowheads) of

the anterior mitral valve leaflet. VS, ventricular septum. B: M-mode echocardiogram showing midsystolic

aortic valve notching (arrow).

It should be noted that asymmetric hypertrophy can occur in

other settings (e.g. RVH, HTN), and SAM of MV can be seen in

other hyperdynamic cardiac conditions. The morphologicalvariants are listed in table 42.

Table 42. Frequency of variants in HCMVariant Percentage

Diffuse hypertrophy of septum and anterolateral free wall 70% to 75%

Basal septal hypertrophy 10% to 15%

Concentric hypertrophy 5%

Apical hypertrophy 4%

Lateral wall hypertrophy 1% to 2%

b. Doppler and color flow imaging

CW Doppler can be used to assess the degree of LVOT

obstruction. Typically the apical transducer position gives the

best results however other positions should also be tried. TheDoppler spectral profile of HOCM has a typical dagger-shaped

appearance (Figure 114). Using the simplified Bernoulli

equation the peak instantaneous gradient can be estimated. Thedynamic nature of the obstruction can be documented using

Valsalva or amyl nitrate (Figure115).



110

Figure 114. CW Dopplerspectra from the apex

demonstrating dynamic

LVOT obstruction. Notethe typical Dagger shapedconfiguration (arrow).

The baseline velocity is 3m/s corresponding to a

peak LVOT gradient of 36

mm Hg. With Valsalva

maneuver, the velocity is

increased to 4 m/scorresponding to 64 mm

Hg gradient (From Oh,

1999).

The degree of accompanying MR can also be assessed usingcolor and other Doppler modalities. The MR jet in this setting is

often directed posterolaterally, and occurs after the onset of

LVOT obstruction. Because of its position the MR jet may beconfused with the LVOT velocity during Doppler interrogation.

The duration of flow, color flow assessment, and configuration

of the Doppler spectral profile helps differentiate the two (Figure115). The rising slope of the MR jet in midsystole is usually

perpendicular to the baseline, compared to a curvilinear profile inthe LVOT jet.

Figure 115. CW Doppler

spectra from LVOT

obstruction and MR jetobtained from the apex.

MR in HCM usually

begins at midsystole when

there is SAM of anteriorMV leaflet, therefore the

Doppler spectrum of MR

may resemble that of

LVOT. However, the

rising slope in midsystoleis usually perpendicular to

the baseline in MR,

whereas it is curvilinear in LVOT signal. Furthermore, the MR velocity signal extends beyondejection. Also the MR velocity will always be higher than the LVOT jet velocity (From Oh,

1999).



111

One could also use the peak MR velocity jet to determine themagnitude of the LVOT obstruction.

LV-LA gradient = 4v2 MR

LV pressure = 4v2 MR + LA pressure

LVOT gradient = LV pressure – SBP

c. Diastolic filling pattern

The hypertrophied myocardium causes a marked impairment of

myocardial relaxation. The pattern seen in the mitral inflow isthat of prolonged IVRT, decreased E velocity, prolonged DT,

and increased A velocity (see section on diastolic function).Figure 116 shows a good example of these abnormalities in a patient with HCM.

Figure 116. MV inflowDoppler velocity pattern of

abnormal relaxation in a

patient with HCM. Thetypical features includereduced E velocity,

increased A velocity, and

prolonged DT (From OH,

1999).



112

Coronary Physiology

During rest normal coronary blood flow is approximately 60-90 ml/min per 100 g of

myocardium. It can be affected metabolic, autonomic, and mechanical factors.

Metabolic factors include adenosine, NO, endothelin, and prostaglandins. Adenosine isthe most important factor and is produced by breakdown of high energy phosphates

(ATP), and accumulate during ischemia.Changes in the coronary blood flow with either sympathetic or parasympathetic

stimulation are due predominantly to the accompanying changes in the loading conditions

and contractility. On the other hand mechanical factors have a major effect on thecoronary blood flow. During myocardial contraction, intramyocardial pressure increases,

causing compression of small blood vessels and reduction of coronary blood flow. The

result is a predominant diastolic blood flow pattern (Figure 117). In the left coronary

artery, approximately 60% of blood flow occurs during diastole. In the proximal RCAthe situation is opposite. There is much less vessel compression during low-pressure RV

contraction, with the result that there is much less reduction in blood flow during systole.The blood flow in proximal RCA duringsystole is nearly equal to that during

diastole. In the distal RCA (beyond RV

marginal branch), diastolic flow predominates.

Figure 117. Flow-velocity measurements obtained

in the left main coronary artery (LM) and the

proximal segments of left anterior descending (LAD),left circumflex (CX), and right coronary arteries

(RCA) of a normal patient (From Topol, 1999)

Coronary blood flow is closely correlated with the diastolic pressure-time index (PTI).

PTI = (DBP ς – LVEDP ς ) x t D

Where DBP ς is the average diastolic blood pressure, LVEDP ς is the average LV end-

diastolic pressure, and t D is the average time duration in diastole. The PTI can be altered by changes in aortic diastolic pressure, LV diastolic pressure, and length in diastole (ie

HR). Hence systemic hypotension, increased LVEDP, and tachycardia decrease coronary

blood flow.

With physical or mental stress, the metabolic demands of the myocardium increase andcoronary blood flow must increase to increases MVO2. This increase occurs as a result of

dilatation of resistance vessels. When the resistance vessels are dilated maximally,

coronary blood flow can not be increased further without an increase in aortic pressure.



113

The ratio of maximal blood flow to resting (or basal) blood flow is termed coronary flow

reserve (CFR).

CFR = Maximal coronary blood flow Resting coronary blood flow

.

Table 43. Coronary flow reserves in angiographically normal arteries

LAD RCA CX

CFR 2.68 2.81 2.39

Table 43 shows the coronary flow reserves in normal subjects. The average CFR appears

to be 2.5 for normal arteries, and there does not seem to be a difference between the three

main coronary arteries.

The maximal myocardial blood flow in the presence of stenosis is reduced relative to theexpected normal flow in the absence of a stenosis and can be expressed as a fraction of its

normal expected value, if there was no lesion. This value called the fractional flowreserve (FFR MYO) can be derived from pressure data. The proposed equations have been

derived from theoretical models of coronary circulation and have been tested in

experimental models satisfactorily. During maximal hyperemia (with adenosine),coronary resistance is at the lowest level and remains constant, so that the flow is directly

related to the measured pressure gradient. The total myocardial blood flow (Q) in a n

area de-served by a coronary artery with a stenosis is the sum of the flow through thestenosis (Qs) and the collateral flow (Qc). The FFR MYO is the ratio of the measured flow

(Q) over the maximal flow that should be present without any stenosis (Q N

):

FFR MYO = Q/Q N

= (P D – P V )/R

(P A – P V )/R

PA = mean arterial pressure; PV = mean venous pressure; PD = mean pressure distal tothe stenosis, and R = the resistance of the myocardial vascular bed.



114

Figure 118. Flow velocity recording (Top) in

the proximal LAD artery. The diastolic tosystolic velocity ratio (DSVR) is

automatically calculated and displayed. The

comparison between diastolic and systoliccomponents (Bottom panel) can be based on

peak velocities in diastole and systole (PVd

and PVs) or, more correctly, on the flowintegrals (DVi/SVi). (from Topol, 1999)

Simplifying this equation further we get:

FFR MYO = (P D – P V ) = 1 – _ ∆ P ~ = P D Assuming a low and constant P V

(P A – P V ) (P A – P V ) P A

For a normal vessel FFR MYO = 100%. This is a lesion specific index independent of

microcirculation, HR, and other hemodynamic variables, and it can be applied tomultivessel disease. Fractional collateral flow reserve (FFR COLL) and fractional coronary

flow reserve (FFR COR ) are calculated with similar equations as follows:

FFRCOR = 1 – ∆ P_

(P A – P W )

FFRCOLL = FFR MYO – FFRCOR

With PW = the coronary wedge pressure measured distally when PTCA balloon is inflated

in the artery.



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