Congenital Heart DiseasesCongenital Heart Diseases

-Congenital heart disease is a general term used to describe abnormalities of the heart or great vessels that are present from birth. -Most such disorders arise from faulty embryogenesis, during gestational weeks 3 through 9, when major cardiovascular structures undergo development.

Normal Circulation

• The aortic valve shows three thin and delicate cusps. The coronary artery orifices can be seen just above.The endocardium is smooth, beneath which can be seen a red-brown myocardium. The aorta above the valve displays a smooth intima with no atherosclerosis.

• This is the tricuspid valve. The leaflets are thin and delicate. Just like the mitral valve, the leaflets have thin chordae tendineae that attach the leaflet margins to the papillary muscles of the ventricular wall below.

• This is a normal coronary artery. The lumen is large, without any narrowing by atheromatous plaque. The muscular arterial wall is of normal proportion.

Incidence & Etiology of congenital heart abnormalities:• 0.8% of live births (high with still births)• Common cause of heart failure in

children• 90% unknown etiology• Chronic alcoholism (Ventricular Septal Defect)

• Rubella (Patent Ductus Arteriosus, Atrial Septal Defect, Pulmonary Stenosis, etc.)

Etiology

Multifactorial, genetic and environmental inputs, however, are suspected, including:

• chromosomal defects (trisomi 13, 21,18 and 5p deletion, 45X-Turner Syndrome)

• viruses, • Chemicals, drugs such as thalidomide, • radiation. • Alcohol consumption of mother during

pregnancy causes fetal cardiac abnormalities

Classification

Clinical Consequences

The varied structural anomalies in hearts with congenital defects fall primarily into two major categories:

• Shunts (cyanotic)• Obstructions (acyanotic).

• A shunt is an abnormal communication between chambers or blood vessels (or both).

• Abnormal channels permit the flow of blood from left to right or the reverse, depending on pressure relationships.

• When blood from the right side of the heart enters the left side (right-to-left shunt), a dusky blueness of the skin and mucous membranes (cyanosis) results because poorly oxygenated blood enters the systemic circulation (cyanotic congenital heart disease; blue baby).

Severe, long-standing cyanosis

• Clubbing of the tips of the fingers and toes (hypertrophic osteoarthropathy)

• Polycythemia (cerebral thrombosis).

• Left-to-right shunts are not initially associated with cyanosis, but these can result in progressive pulmonary hypertension and right ventricular overload with hypertrophy.

• Late cyanosis.

Congenital Heart Diseases• Left-to-Right shunts.Left-to-Right shunts.

• Atrial Septal Defect (ASD)• Ventricular Septal Defect (VSD)• Patent Ductus Arteriosus (PDA)• Atrioventricular Septal Defect (AVSD)

• Right-to-Left shuntsRight-to-Left shunts• Tetralogy of Fallot• Transposition of Great Arteries

• ObstructionsObstructions• Coarctation of Aorta• Aortic Stenosis & Atresia

• Atrophy/Hypoplasia/AbnAtrophy/Hypoplasia/Abnormalities of the ormalities of the ValvesValves

Left to Right Shunts Defect Mechanism

Ventricular SeptalDefect

There is a hole within the membranous or muscular portions of the inter-ventricular septum that produces a left-to-right shunt, more severe with larger defects. The most extreme example is "cor triloculare biatrium", with no septum at all.

Atrial

Septal

Defect

A hole in the inter-atrial septum produces a modest left-to-right shunt. Lutembacher's syndrome merely refers to mitral stenosis plus an atrial septal defect.

PatentDuctus

Arteriosus

The ductus arteriosus, which normally closes soon after birth, remains open, and a left-to-right shunt develops.

Disease Incidence %Ventricular septal defect 32 Atrial septal defect 8 Patent ductus arteriosus 8Pulmonic stenosis 8Tetralogy of Fallot 8 Coarctation of the aorta 7Aortic stenosis 6Transposition of great arteries 5Persistent truncus arteriosus 1All others 8

Ventricular Septal Defect (VSD)

• There is a hole within the membranous or muscular portions of the intraventricular septum that produces a left-to-right shunt, more severe with larger defects

VSD is classified according to its size.

• 2.1. Small VSD (Maladie de Roger): • Small VSDs (< 0.5 cm in diameter) are

common. They produce a low-volume shunt from the left to the right ventricle during systole.

• This shunt across a high pressure gradient produces a loud pansystolic murmur heard best at the left sternal edge. With a small defect, right ventricular pressure is increased only slightly.

• Cardiac catheterization shows entry of oxygenated blood into the right ventricle.

• 2.2. Large VSD: • A large VSD is much more serious, with

clinical manifestations appearing in early childhood.

• Initially, a large volume of blood is shunted from the left to the right ventricle during systole, producing volume overload of both ventricles, hypertrophy of both ventricles, and a pansystolic murmur.

Ventricular Septal Defect (VSD)

• Increased blood flow through the pulmonary circulation induces pulmonary hypertension and a loud pulmonary-valve closure sound.

• Progressive thickening and narrowing of the small pulmonary arteries leads to increase in right ventricular pressure, reduction in shunt volume and, finally, shunt reversal.

• This produces cyanosis (Eisenmenger's syndrome). Shunt reversal in VSD occurs some time after birth (tardive cyanosis) and is associated with decrease or disappearance of the pansystolic murmur.

• Patients with VSD are at risk for infective endocarditis.

ASD & VSD• Small Defects

• No significant shunt

• Source of Infection

• Infective endocarditis

Atrial Septal Defect (ASD)

• A hole in the inter-atrial septum produces a modest left-to-right shunt.

• Enlarged right heart, & pulmonary vessels.

1.1. Ostium Secundum ASD :

• The most common type of ASD is a defect in the development of the septum secundum, which produces mild disease that is frequently not detected until adult life.

• In most cases of ostium secundum ASD, the defect is large enough (> 2 cm) to cause near equalization of left and right atrial pressure, with flow of blood from left to right through the ASD. In the usual case, pulmonary flow is increased to about twice that of systemic output, and the right ventricle is dilated and hypertrophied owing to the volume overload.

• This is usually well tolerated, and right ventricular failure is uncommon.

• The main complication of ostium secundum ASD is the development of pulmonary hypertension, increased right side pressure, and either right heart failure or reversal of the shunt and cyanosis. Paradoxic embolization to the systemic circulation and infective endocarditis may occur.

1.2. Ostium Primum ASD:

• Ostium primum defects are rare, constituting about 5% of all cases of ASD. They occur as large defects in the lower part of the atrial septum and are often associated with mitral valve lesions.

• Ostium primum defect is common in Down syndrome.

• Ostium primum ASD produces severe disease in early childhood, with features of mitral incompetence superimposed on the ASD.

Atrial Septal Defect (ASD)

Atrial Septal Defect (ASD)

Patent Ductus Arteriosus (PDA)• The ductus arteriosus,

serves to shunt blood from pulmonary artery to aorta during intrauterine life.

• Persistence of ductus, which normally closes soon after birth, results in left-to-right shunt develops.

• Leading to pulmonary hypertension.

Patent Ductus Arteriosus - Infant

Endocardial Cushion Defect:Atrioventricular septal defect

Endocardial Cushion Defect

Tetralogy of Fallot

Pulmonary stenosis results in right ventricular hypertrophy and a right-to-left shunt across a VSD, which also has an overriding aorta

Transposition

of Great Vessels

The aorta arises from the right ventricle and the pulmonary trunk from the left ventricle. A VSD, or ASD with PDA, is needed for extrauterine survival. There is right-to-left shunting

Truncus Arteriosus

There is incomplete separation of the aortic and pulmonary outflows, along with VSD, which allows mixing of oxygenated and deoxygenated blood and right-to-left shunting

Right to Left Shunts

Tetralogy of Fallot• Pulmonic stenosis (the

aorta crunching it closed) results in right ventricular hypertrophy and a right-to-left shunt across a high VSD, which also has an overriding aorta (aorta straddles the ventricular septum).

• Common cause of cyanotic heart disease.

• Tetralogy of Fallot is the most common cyanotic congenital cardiac anomaly.

• It is characterized by: • (1) a large ventricular septal defect; • (2) stenosis of the pulmonary outflow tract; • (3) dextroposition of the aorta, which

overrides the right ventricle; and • (4) hypertrophy of the right ventricle. • The pulmonary stenosis raises right

ventricular pressure so that the shunt across the VSD is right-to-left, with venous admixture of systemic arterial blood causing cyanosis.

Transposition of Great Vessels• The aorta arises from

the right ventricle and the pulmonic trunk from the left ventricle

• a VSD, or ASD with PDA, is needed for extrauterine survival.

• There is right-to-left shunting.

in Transposition of Great Vessels

• The blood flow is: • right atriumright ventricleaorta • left atriumleft ventriclepulmonary

artery • If the child is to survive for any length of

time after birth, an atrial or ventricular septal defect must be present.

• This malformation is lethal.

ObstructionsPulmonary Stenosis/Atresia with Intact Ventricular Septum

Obstruction at the pulmonary valve. When the valve is entirely atretic, the anomaly is commonly associated with a hypoplastic right ventricle and an ASD.

Coarctation of Aorta

Either just proximal (infantile form) or just distal (adult form) to the ductus arteriosus is a narrowing of the aortic lumen, leading to outflow obstruction

Aortic Stenosis and Atresia

The aortic valvular orifice may be narrowed or stenosed by acquired disease (RHD, degenerative calcific aortic stenosis), by anomalous development (atresia or stenosis), or by a combination of both (calcification of a congenitally malformed valve).

Coarctation of Aorta

• Either just proximal (infantile form) or just distal (adult form) to the ductus is a narrowing of the aortic lumen, leading to outflow obstruction.

• Common in Turner's syndrome.

Coarctation of Aorta (Infant)

Coarctation of Aorta

Coarctation of Aorta

• Since the lower half of the body is likely to be under-perfused (claudication, etc.),

• Renal hypertension is usual, • If the femoral pulses on a hypertensive

patient seem late and weak, it's probably coarctation of the aorta.

MALPOSITIONS of the HEART

• An acardius is a birth defect in which there is no heart. If the pregnancy goes to term, it is always because the child shares circulation with a twin.

• Dextrocardia means the heart's on the right side.

• In situs inversus totalis, with everything backwards, the heart is usually well-formed.

• If the heart is the only organ that is mal-positioned, it often bears other defects.

What kind of abnormality is shown here?

•Quadricuspid Quadricuspid pulmonary pulmonary valve.valve.