heart diseases lecture i associate professor dr. alexey podcheko spring 2015

HEARTDISEASESLecture I

Associate Professor Dr. Alexey Podcheko

Spring 2015

INTENDED LEARNING OUTCOMES

CONGENITAL (CHD):

1. To know Cardiac Development

2. To know causes of CHD

3. Pathophysiology and clinical presentations of:• ASD, VSD, patent ductus arteriosus (PDA)

• Tetralogy of Fallot

• Transposition of the great arteries

• Persistent Truncus arteriosus

• Tricuspid atresia

• Total anomalous pulmonary venous connection

• COARCTATION of aorta

• pulmonary stenosis/atresia

• Aortic stenosis/atresia

THE HEART• Normal• Pathology

– Heart Failure: L, R– Heart Disease

• Congenital: LR shunts, RL shunts, Obstrustive• Ischemic: Angina, Infarction, Chronic Ischemia, Sudden Death• Hypertensive: Left sided, Right sided• Valvular: AS, MVP, Rheumatic, Infective, Non-Infective,

Carcinoid, Artificial Valves• Cardiomyopathy: Dilated, Hypertrophic, Restrictive, Myocarditis,

Other• Pericardium: Effusions, Pericarditis• Tumors: Primary, Effects of Other Primaries• Transplants

NORMAL Features• 6000 L/day• 250 to 300 gm in females and 300 to 350 gm in

males, or roughly 0.4% to 0.5% of body weight• 40% of all deaths (2x cancer)• Wall thickness ~ pressure• (i.e., a wall is only as thick as it has to be)

-Right ventricle - 0.3 to 0.5 cm

-Left ventricle 1.3 to 1.5 cm

-Atria =.2 cm

Normal Features, Starling's Law of the Heart

• ability of the heart to change its force of contraction and therefore stroke volume in response to changes in venous return is called the Frank-Starling mechanism (or Starling's Law of the heart).

• The efficient pumping of blood by the heart to the entire body requires the normal function of each of its key components:

• 1. the myocardium

• 2. valves

• 3. conduction system

• 4. coronary arterial circulation

NORMAL Features

Which one is cardiac tissue?

A BCardiac muscle cell has one nucleus (sometimes two).Each cardiac muscle cell is branched, forming a tissue that is

appropriately described as a functional syncytium

Intercalated disks junctions types :1. Fascia adherens2. Desmosomes3. Gap junctions (exchange of ions)

CONDUCTION SYSTEM of the HEART

• Needed for coordinated contraction of the cardiac muscle

• Presented by specialized excitatory and conducting myocytes

• Key components :• (1) the sinoatrial (SA) pacemaker of

the heart, (near the junction of the right atrial appendage and the superior vena cava)

• (2) the AV node (in the right atrium along the atrial septum)

• (3) the bundle of His (courses from the right atrium to the summit of the ventricular septum)

• (4) the right and left bundle branches, Left bundle brunch has anterior and posterior fascicles!!!

• (5) Purkinje network

S.A. NodeAV NodeBundle of HIS L. Bundle, R. Bundle

Coronary arterial circulation• To meet their energy needs, cardiac myocytes rely almost

exclusively on oxidative phosphorylation, which is manifest by the abundant mitochondria that are found in these cells

• cardiac myocytes extremely vulnerable to ischemia • Coronary arteries: -epicardial coronary arteries:1. Left Coronary artery (LCA)a. left anterior descending (LAD) b. left circumflex (LCX) arteries, both arising from branches of

the left (main) coronary artery2. Right Coronary artery (RCA)a. Marginal b. Posterior descending artery (in 85% of cases) and nodal

artery• Most coronary arterial blood flow to the myocardium

occurs during ventricular diastole

Whichever artery winds up supplying the posterior interventricular septum is said to be “DOMINANT”

VALVES• AV:

–TRICUSPID

–MITRAL

• SEMILUNAR:–PULMONIC

–AORTIC

Valves• Their function depends on the mobility, pliability, and structural

integrity of their delicate flaps, called leaflets (in the tricuspid and mitral valves) or cusps (in the aortic and pulmonary valves, also known as the semilunar valves).

• layered architecture :• 1. lamina ventricularis (tight network of reticular fibres  )• 2. lamina radialis (radial orientated collagenous and elastic

fibres)• 3. lamina spongiosa (loosely arranged reticular fibres with

bundles of collagenous and some elastic fibres)• 4. lamina fibrosa (Circular arranged collagen fibres )• 5. lamina arterialis

Schematic drawing of aortic root structures after longitudinal opening of the root.

Schematic drawing of aortic root structures after longitudinal opening of the root.

• The function of the semilunar valves depends on the integrity and coordinated movements of the cuspal attachments.

• Dilation of the aortic root can hinder cooptation of the aortic valve cusps during closure, yielding regurgitation.

• The competence of the atrioventricular valves depends on not only the leaflets and their attachments, but also on tendinous connections to the papillary muscles of the ventricular wall.

VALVES

Heart Pathology

• In the United States, heart disease accounts for nearly 40% of all postnatal deaths, totaling about 750,000 individuals annually; this is nearly 1.5 times the number of deaths caused by all forms of cancer combined

• one third of Americans have one or more types of cardiovascular disease

HEART DISEASE

•CONGENITAL (CHD)• ISCHEMIC (IHD)

• HYPERTENSIVE (HHD)

• VALVULAR (VHD)

• MYOPATHIC (MHD)

INTENDED LEARNING OUTCOMES

CONGENITAL (CHD):

1. To know Cardiac Development

2. To know causes of CHD

3. Pathophysiology and clinical presentations of:• ASD, VSD, patent ductus arteriosus (PDA)

• Tetralogy of Fallot

• Transposition of the great arteries

• Persistent Truncus arteriosus

• Tricuspid atresia

• Total anomalous pulmonary venous connection

• COARCTATION of aorta

• pulmonary stenosis/atresia

• Aortic stenosis/atresia

CONGENITAL HEARTDEFECTS

• Faulty embryogenesis (week 3-8)• Usually MONO-morphic (i.e., SINGLE lesion)

• Approximately half of congenital cardiovascular malformations are diagnosed in the first year of life

• May not be evident until adult life (Coarctation, ASD)

• Overall incidence 1% of USA births• Most defects are sporadic, but there are some

genetic syndromes associated with congenital heart disease

Total anomalous pulmonary venous connection

Tricuspid atresia

1

<1 120 

1 136 Truncus arteriosus

4 388 Transposition of great arteries

4 388 Aortic stenosis

4 396 Atrioventricular septal defect

5 492 Coarctation of aorta

5 577 Tetralogy of Fallot

7 781 Patent ductus arteriosus8 836 3. Pulmonary stenosis101043

2. Atrial septal defect

4244821.Ventricular septal defect%

Incidence per Million Live BirthsMalformation

Most Common CHD in US

Cardiac Development

1.Day 15: heart cell precursors of mesoderm moving to the mid-line in two migratory waves to create a crescent of cells consisting of the first and second heart fields

2.Day 20 (Week3), the initial cell crescent develops into a beating tube

Cardiac Development

3. Day 28 (WEEK4) beginning formation of heart chambers, rightward looping of the heart tube, cardiac neural crest cells (blue) migrate (arrow) into the outflow tract and pattern the bilaterally symmetric aortic arch arteries

4. Day 50 (WEEK 7) Septation of the ventricles, atria, and atrioventricular valves (AVV) results in the appropriately configured four-chambered heart

GENETICS of CHD

1. Most common genetic cause of congenital heart disease is trisomy 21 (Down syndrome)

2. Trisomy 13, 15, 18 or Turner (XO) – Coarctation of Aorta!

3. 22q11.2 deletion (DiGeorge syndrome aka CATCH22)Tetralogy of Fallot, aortic arch abnormalities

4. Marfan Syndrome – cystic medial degeneration of aorta – aortic aneurism

5. Tuberous Sclerosis (mutation of tumor suppressor genes TSC) – valvular obstructions due to cardiac rhabdomyomas in newborns

6. Friderich Ataxia – Hypertrophic cardiomyopathy

Father has VSD – for child risk is 2%Mother has VSD – for child risk 6-10%

ENVIRONMENT1. RUBELLA

2. TERATOGENS

3. gestational diabetes

4. Folic acid deficiency

CHD CLASSIFICATION I. A shunt is an abnormal communication between

chambers or blood vessels • LR SHUNTS: all “D’s” in their names (ASD, VSD,

ASVD, and patent ductus arteriosus- PDA )– NO cyanosis– Pulmonary hypertension present– Prolonged pulmonary hypertension is IRREVERSIBLE

• RL SHUNTS: all “T’s” in their names (Tetralogy of Fallot, Transposition of the great arteries, persistent Truncus arteriosus, Tricuspid atresia, Total anomalous pulmonary venous connection)– CYANOSIS (i,.e., “blue” babies)– VENOUS EMBOLI become SYSTEMIC

II. OBSTRUCTIONS (coarctation of the aorta, aortic valvular stenosis, pulmonary valvular stenosis )

Septum primum migrates downSeptum Primum

Septum Secundum

Ventricular Septum

Septum Secundum migrates up

Ventricular Septum

migrates up

Formation of Atrial and Ventricular defects

ASD• Abnormal, fixed opening in the

atrial septum caused by incomplete tissue formation that allows communication of blood between the left and right atria

• Usually asymptomatic until adulthood

3 Main Types: • SECUNDUM (90%): Defective

fossa ovalis (B, E)• PRIMUM (5%): Next to AV valves,

mitral cleft defect –it associated with Down Syndrome!!! (D)

• SINUS VENOSUS (5%): Next to SVC with anomalous pulmonary veins draining to SVC or IVC (A and C)

Patent foramen ovale• A small hole created by an open flap of

tissue in the atrial septum at the oval fossa.

• Normally, foramen ovale is an important functional right-to-left shunt that allows oxygen-rich blood from the placenta to bypass the not yet inflated lungs

• The hole is forced shut at birth in 80% of cases

• Sustained pulmonary hypertension or even transient increases in right-sided pressures, such as occurs during a bowel movement, coughing, or sneezing, can produce brief periods of right-to-left shunting, with the possibility of paradoxical embolism

ASD Clinical Features• Splitting of S1 and S2 sounds, crescendo-

decrescendo systolic murmur in the  second intercostal space at the upper left sternal border.

• Paradoxal embolism (emboli from veins in systemic arteries)

• ASDs do not become symptomatic before age 30 (why?)

• Irreversible pulmonary hypertension is unusual, but LARGE defects may progress to pulmonary hypertension and reverse of the shunt which will lead to cyanosis (aka Eisenmenger syndrome)

• Surgical or catheter-based closure of an ASD reverses the hemodynamic abnormalities and prevents complications, including heart failure, paradoxical embolization, and irreversible pulmonary vascular disease.

• Long-term survival is comparable to that of a normal population

ASD treatment and prognosis

VSD

• Most common CHD defect

• Incomplete closure of the ventricular septum

• Only 30% are isolated (Often associated with TETRALOGY of FALLOT)

• MC Associated with fetal alcohol syndrome

• 90% involve the membranous septum

• Infundibular VSD - below the pulmonary valve

• Muscular septum VSD, likely to have multiple holes (“Swiss-cheese” septum )

• SMALL ones often close spontaneously

• LARGE ones progress to pulmonary hypertension and reverse of the shunt which will lead to cyanosis (aka Eisenmenger syndrome)

VSD Morphology

Infundibular VSD - below the pulmonary valve

Clinical presentation of VSD

• Low Pitched HoloSystolic murmur, accentuation with handgrip exercise

• Splitting of S2

• Polycythemia

• Clubbing of digits

• Paradoxal embolization

• Rx: Surgical closure

• A 7-year old boy is brought to the pediatrician by his mother for a routine check-up. He has no complains. Cardiac auscultation findings at the left sternal border are given below. The findings accentuate with the handgrip exercise Which of The following is the most likely diagnosis?

• A Atrial septal defect

• B. Hypertrophic cardiomyopathy

• C. Patent ductus arteriousus

• D. Ventricular septal defect

• E. Aortic regurgitation

Physiologic ways to increase intensivity of murmurs

PDA (Persistent ductus arteriosus)

• DA should be closed within 12-24hrs after birth

• 90% of PDAs isolated• 10% associated with VSD, or

coarctation of the aorta, or pulmonary or aortic valve stenosis

• Associated with congenital rubella

• PGE kEEps PDA open• At the beginning is left to right shunt

but later is switched to right to left (Eisenmenger syndrome)

PDA Clinic

• HOLOSYSTOLIC HARSH, machinery-like murmur

• LR, possibly RL as pulmonary hypertension approaches systemic pressure with development of cyanosis

• Closing the defect may be life saving

• Indomethacin causes closure of PDA

• A 10-year-old immigrant from Eastern Europe is brought to the physician because of exertional dyspnea and easy fatigability. According to his parents, he was diagnosed with a congenital heart disease in infancy for which they refused treatment. They cannot recall the details of his diagnosis. Physical examination reveals toe cyanosis and clubbing but no finger abnormalities. This patient most likely suffers from which of the following?

• A. Primum-type atrial septal defect• B. Secundum-type atrial septal defect• C. Ventricular septal defect • D. Patent ductus arteriosus • E. Coarctation of the aorta • F. Tetralogy of Fallot

AVSD• Associated with

defective, inadequate AV valves

• The two most common forms are partial AVSD (consisting of a primum ASD and a cleft anterior mitral leaflet, causing mitral insufficiency) and complete AVSD (a hole in the center of the heart).

• More that 1/3 of all patients with a complete AVSD have Down syndrome.

• Rx: surgery

RL SHUNT – 5Ts

1. Tetralogy of Fallot

2. Transposition of great arteries

3. Truncus arteriosus

4. Total anomalous pulmonary venous connection

5. Tricuspid atresia

RL SHUNTS• TETRALOGY of FALLOT most COMMON

– 1) LARGE Ventricular Septal Defect– 2) OBSTRUCTION to blood flow from RV

into Pulmonary artery– 3) Aorta OVERRIDES the VSD– 4) Right Ventricular Hypertrophy– SURVIVAL DEPENDS on SEVERITY of

SUBPULMONIC STENOSIS– Can be a “PINK” tetrology if pulmonic

obstruction is small, but the greater the obstruction, the greater is the RL shunt

1) VSD, large2) OBSTRUCTION to RV flow3) Aorta OVERRIDES the VSD4) RVH (not shown on this picture)10% alive at 20 years and 3% at 40 years

Clinical Features:

CLASSICAL “TETROLOGY” of FALLOT

Clinical features• Physical exercises cause

cyanosis in this patients (cyanotic spells)

• Squatting alleviate cyanosis !!!

• Degree of pulmonic stenosis determines extent of shunting and cyanosis

• CXR – boot shaped heart

• Auscultation: diamond shaped systolic murmur

• A 2-week-old girl is found to have a harsh murmur along the left sternal border. The parents report that the baby gets “blu-ish” when she cries or drinks from her bottle. Echocardiogram reveals a congenital heart defect associated with pulmonary stenosis, ventricular septal defect, dextroposition of the aorta, and right ventricular hypertrophy. What is the appropriate diagnosis?

(A) Atrial septal defect(B) Coarctation of aorta, postductal(C) Coarctation of aorta, preductal(D) Tetralogy of Fallot(E) Truncus arteriosus

TGA (TRANSPOSITION of GREAT ARTERIES)

Creates two not linked circuits:•PA arises from LV•Aorta arises from RVNEEDS a SHUNT for survival–PDA or PFO (65%), “unstable” shunt –VSD (35%), “stable” shuntQ:What will happen if we close PDA in patient with TGA?A:

TGA Clincal Features

– Associated with maternal diabetes

– RV>LV in thickness– Need to administer PgE to

keep PDA open until surgery– Fatal in first few months if not

correctedRx: - Prostaglandin E - Surgical “switching”– Balloon Septostomy

Possible USMLE Scenario• A 27-year-old woman gives birth to a term infant after an

uncomplicated pregnancy and delivery. The infant is cyanotic at birth. Two months later, physical examination shows the infant to be at the 37th percentile for height and weight. The representative gross appearance of the infant's heart is shown in figure. What is the most likely diagnosis?

(A) Tetralogy of Fallot

(B) Pulmonic stenosis

(C) Truncus arteriosus

(D) Transposition of the great vessels

(E) Aortic stenosis

PERSISTENT TRUNCUS ARTERIOSUS

1.Single large vessel arising from both ventricles!!!

2.Developmental failure of separation of the embryologic truncus arteriosus into the aorta and pulmonary artery

3.Cyanosis4.Danger of irreversible

pulmonary hypertensionEarly diastolic decrescendo

murmur

A 2-week-old boy is irritable and feeding poorly. On physical examination, the infant is irritable, diaphoretic, tachypneic, and tachycardic. There is circumoral cyanosis, which is not alleviated by nasal oxygen. A systolic thrill and holosystolic murmur are heard along the left sternal border. An echocardiogram reveals a heart defect in which the aorta and pulmonary artery form a single vessel that overrides a ventricular septal defect. What is the appropriate diagnosis?

(A) Atrial septal defect(B) Coarctation of aorta, preductal(C) Patent ductus arteriosus(D) Tetralogy of Fallot(E) Truncus arteriosus

TRICUSPID ATRESIA

• Tricuspid valve orifice fails to form

• Hypoplastic RV

• Needs a shunt, ASD, VSD, or PDA

Signs: • Soft S1 sound

• Low PCWP (wedge pressure)

• RA hypertrophy – dilation of P wave on ECG

•Early Cyanosis and high mortality in first week

Main message:

• pulmonary atresia, tricuspid atresia, Tetralogy of Fallot, Transposition of the great vessels – administer prostaglandin to keep DA open or child will die!

Total Anomalous Pulmonary Venous Connection (TAPVC)

• PULMONARY VEINS do NOT go into LA, but into L. innominate v. or coronary sinus

• Needs a PFO or a VSD

• HYPOPLASTIC LA• Do not administer

Prostaglandin E1

OBSTRUCTIVE CHD• COARCTATION of aorta

• Pulmonary stenosis/atresia

• Aortic stenosis/atresia

COARCTATION of AORTA• Coarctation=narrowing of

aorta• Two major forms:

INFANTILE and ADULT

(pre- and postductal)• “Infantile” form:

hypoplasia of the aortic arch proximal to a patent ductus arteriosus

• symptomatic in early childhood

Infantile form (preductal) COARCTATION of AORTA

• Associated with presence of patent ductus arteriosus

• Presents with lower part of the body cyanosis, upper extremities are ok

• XO’s (Turner syndrome) frequently have it with shortening of 4th metacarpal bone and horse-shoe kidney!!!

• Discrete ridgelike infolding of the aorta, just opposite the closed ductus arteriosus (ligamentum arteriosum) distal to the arch vessels

• Bicuspid aortic valve 50% of the time (prone to aortic stenosis)

• Associated with congenital aortic stenosis, ASD, VSD, mitral regurgitation, or berry aneurysms of the circle of Willis in the brain

Adult form of COARCTATION of AORTA

Clinical manifestations Adult form of COARCTATION of AORTA

• Hypertension in the upper extremities

• Development of collateral circulation between the precoarctation arterial branches and the postcoarctation arteries through enlarged intercostal and internal mammary arteries, which produce radiographically visible erosions (“notching”) of the undersurfaces of the ribs

• Murmurs are present throughout systole, ; sometimes a thrill

• Cardiomegaly due to left ventricular pressure-overload hypertrophy

Prognosis for Adult form of COARCTATION of AORTA

Patients with adult-type coarctation of the aorta commonly die of hypertension-associated complications:

left ventricular failure

ruptured dissecting aortic aneurysm

intracranial hemorrhage (due to the increased incidence of congenital berry aneurysms of the Circle of Willis)

• A 22-year-old Caucasian male presents to the emergency room complaining of severe headaches and vomiting. Soon after, he slips into a coma and dies. Autopsy shows a ruptured cerebral aneurysm with extensive intracranial hemorrhage. This patients condition is most likely associated with:

A. Primum-type atrial septal defect

B. Secundum-type atrial septal defect

C. Ventricular septal defect

D. Patent ductus artenosus

E. Coarctation of the aorta

F. Tetralogy of Fallot

Pulmonary Valve Stenosis and Atresia • PS- an obstruction at the

pulmonary valve• Lesion can be isolated or part of

a more complex anomaly—either tetralogy of Fallot or transposition of the great arteries

• Right ventricular hypertrophy is often

• Poststenotic dilation of the pulmonary artery due to injury of the wall by “jetting” blood.

• When the valve is entirely atretic, there is an ASD and blood reaches the lungs through a patent ductus arteriosus.

• Clinical severity ~ stenosis severity

AORTIC VALVE STENOSIS/ATRESIA

• Stenosis - Three locations: • valvular, • subvalvular, • supravalvular

• Atresia leads to underdevelopment (hypoplasia) of the left ventricle and ascending aorta, sometimes accompanied by dense, porcelain-like left ventricular endocardial fibroelastosis

• The ductus arteriosus is open to allow blood flow to the aorta and coronary arteries

• when the ductus will be closed it will lead to the child death

• Less severe degrees of congenital aortic stenosis may be compatible with long survival

• Congenital aortic stenosis is an isolated lesion in 80% of cases.

MITRAL VALVE PROLAPSE: CLINICAL FEATURES

• displacement of an abnormally thickened mitral valve leaflet into the left atrium during systole

• Usually asymptomatic• Mid-systolic “click”• Holosystolic murmur if regurg. present• Occasional chest pain,

dyspnea• 97% NO untoward effects• 3% Infective endocarditis,

mitral insufficiency, arrythmias, sudden death

Ebstein anomaly

• Congenital heart defect in which the septal leaflet of the tricuspid valve is displaced towards the apex of the right ventricle of the heart

• Etiology: Fetal exposure to Lithium !!!!

• Systolic murmur of tricuspid regurgitation

• Mid-diastolic murmur along the lower left sternal border

• Right atrial hypertrophy• WPW syndrome on ECG