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Advanced Concepts in

Pressure-Volume Analysis

Daniel Burkhoff MD PhD Adjunct Associate Professor

Columbia University

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If your research involves studying the effects of altered

genes, cells, extracellular matrix, drugs, etc, on

cardiovascular properties, there are several key

concepts, indexes and measurement techniques you

should be aware of:

PRELOAD

AFTERLOAD

CONTRACTILITY

LUSITROPY

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Resources

Harvi Interactive, simulation-based textbook for

the iPad

iPad 2, 3 and mini (iOS 6)

0 25 50 75 100 125 150 0

25

50

75

100

125

150

LV Volume (ml)

LV

Pre

ss

ure

(m

mH

g)

MV Closes

AoV Opens

AoV

Closes

MV

Opens

Iso

vo

lum

ic

Co

ntr

ac

tio

n

Iso

vo

lum

ic

Rela

xa

tion

Filling

Ejection

The Cardiac Cycle Pressures-Volumes Loop

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25

50

75

100

125

150

LV Volume (ml)

LV

Pre

ss

ure

(m

mH

g)

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Pressure-Volume Loops and Relationships

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EDPVR and ESPVR define the boundaries within

which the PV Loop sits, independent

of “preload” and “afterload”

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50

75

100

125

150

LV Volume (ml)

LV

Pre

ssu

re (

mm

Hg

)

Vo

Ees

End-Systolic Pressure-Volume

Relationship

(ESPVR)

Pes = Ees(Ves-Vo)

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End-Systolic Pressure-Volume Relationship

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Contractility: The concept applied to the Left Ventricle

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LV Volume (ml)

LV

Pre

ss

ure

(m

mH

g)

Ees Ees

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Contractility

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LV Volume (ml)

LV

Pre

ss

ure

(mm

Hg

)

10

20

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End-Diastolic Pressure-Volume Relationship 11

Vo

P = β(eα(V-Vo)-1)

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Lusitropy: Passive Diastolic Properties

0 125 250 0

LV Volume (ml)

LV

Pre

ssu

re

(mm

Hg

)

10

20

30

Diastolic Capacitance

= volume at a given pressure

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Lusitropy: Passive Diastolic Properties

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ESPVR: Advanced Concepts

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ESPVR: Advanced Concepts

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ESPVR: Advanced Concepts

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Possible ESPVR Changes in Response to Intervention

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ESPVR:

Practical Recommendations

• Linear regression over the range of available data

• Report both Ees and Vo

• Use Analysis of Covariance (or multiple linear

regression analysis with dummy variables) to

compare ESPVRs measured under different

conditions • Do not use t-tests compare slopes or Vo values

• An alternative is to use volume and a specified

pressure (e.g., V120)

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EDPVR: Advanced Concepts

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EDPVR: Advanced Concepts

P=βVα

P= β(eα(V-Vo)-1)

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EDPVR: Advanced Concepts

EDPVR can be linearized by

logarithmic transformation:

P=βVα

Ln(P) = Ln(β) + αLn(V)

As for ESPVR:

• Report both values of α and β

• Use analysis of covariance to

assess for shifts of EDPVR

0

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30

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50

0 50 100 150 200

y = 4x - 7

-5

-4

-3

-2

-1

0

1

2

0.5 1 1.5 2 2.5

Pressure-Volume

Ln(P) – Ln(V)

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EDPVR: Alternative Analsyis V30

Questions

Physiology & Hemodynamic Concepts

• What is the importance of Tau?

• What conformational changes occur in a PV loop plot, other than a rightward shift of the PV-loops, that confirm the subject has heart failure?

• What is Arterio-Ventricular Coupling?

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0 50 100 150 0

25

50

75

100

125

150

LV Volume (ml)

LV

Pre

ssu

re (

mm

Hg

)

EDV

SV

Pes MAP

25 Ventricular-Vascular Coupling on the PV Diagram

Physiology & Hemodynamic Concepts

• In HF do PV loops maintain their classical shape? In this case, are there changes to the way hemodynamics are calculated (ie. SV, SW, CO)?

• What is the effect of heart valve disorders on PV Loops (aortic stenosis and mitral valve incompetence)?

• Besides differences in pressure, how would RV PV loops differ from LV PV loops?

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ESPVR in CHF

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PV Loops in Valve Lesions

Normal AS MR

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RV vs LV PV Loops

Methodology & Best-Practices

• How can PV loops be used to assess the cardiac safety

of new drugs? Do you see this as a requirement?

• How many PV loops should be included for occlusion

data measurements?

• Are there special considerations for PV loop

measurements in isolated working heart models?

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Load-Independent Measurements

• Strain rates and related analyses have been suggested as a load-independent means of measuring myocardial function and can be looked at globally to assess ventricular function in-vivo with techniques like speckle tracking. Can you comment on this and your opinion regarding myocardial strain analysis as a practical, load-independent measure of cardiac function?

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Load-Independent Measurements

• Work by Glower et al indicated the end-systolic pressure volume relationship was relatively load and heart rate independent within a defined physiologic range. What afterload and heart rate ranges do you feel pressure-volume loop relationships are most appropriately utilized?

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