CONGENITAL HEART DISEASES

•	Types.
•	Acyanotic: VSD, PDA, ASD, AVSD, PS, CoA.
•	Cyanotic: ToF, TGA.

Types

1.	Congenital malformations affecting the heart and/or the great vessels occur in a little under 1% of newborn infants.

2.	Relative frequency of common congenital heart defects

Defect	Approximate frequency %	
Ventricular septal defect	30	
Persistent ductus arteriosus	12	
Atrial septal defect	8	
Pulmonary stenosis	8	
Aortic stenosis	5	
Coarctation of aorta	5	
Tetralogy of Fallot	5	
Transposition of great arteries	5	

3.	Acyanotic defects

a.	Comprise 75% of all congenital heart defects.

b.	Associated with an isolated left to right shunt, e.g. VSD, ASD.

c.	Those which are not associated with any shunting, in which no septal defect is present, e.g. pulmonary stenosis.

4.	Cyanotic defects

a.	Comprise 25% of all congenital heart defects.

b.	Right to left shunt: deoxygenated blood from the systemic venous system is being directed back into the systemic circulation without transiting the pulmonary vascular bed.

c.	All such defects are associated with the presence of a septal defect coupled with additional abnormalities which alter the pressure relationship between two sides of the heart.

d.	Three major subgroups exist:

i.	pulmonary flow is reduced due to obstruction to normal flow into lung circulation and a septal defect behind obstruction through which blood may shunt from right to left, e.g. tetralogy of Fallot.

ii.	bidirectional shunting is associated with very large communications between the left and right sides of the heart with free mixing of blood, e.g. single ventricle.

iii.	transposition of great arteries: the aorta and pulmonary artery are connected to the wrong side of the heart and as a result systemic venous blood is directed straight through into the systemic circulation again.

4.	The major presenting features are:

a.	Presence of an abnormal murmur.

b.	Development of symptoms or signs of congestive heart failure.

c.	Central cyanosis.

d.	Any combination of the above.

Ventricular Septal Defect

1.	Types:

a.	Permembranous: defect is close to the membranous part of the ventricular septum.

b.	Subarterial: beneath the aortic and pulmonary valve.

c.	Muscular: entirely enclosed in the muscular septum.

2.	Symptoms:

a.	Can be asymptomatic.

b.	Dyspnoea with easy tiring.

c.	Failure to thrive.

d.	Recurrent chest infections.

3.	Signs:

a.	Loud harsh PSM at lower left sternal edge frequently associated with a thrill.

b.	P2 may be increased in pulmonary hypertension.

c.	MDM at apex due to increased flow through mitral valve.

d.	Atypical findings with a larger VSD: parasternal heave and displaced apex beat.

e.	VSD need not have PSM since there is no flow if the heart contract and close the hole.

f.	If there is combination of PSM at LSE and MDM at apex and after 6 months, the MDM disappears, this indicates:

i.	pulmonary hypertension is developing.

ii.	VSD getting smaller.

4.	Size of VSD and present signs

Small + moderate VSD with L-to-R shunt	•	Acyanotic, asymptomatic.
•	PSM.
•	No P2.
•	No MDM.	
Large VSD with L-to-R shunt	•	Acyanotic but symptomatic.
•	Hyperactive heart sounds.
•	PSM.
•	No P2.
•	MDM at apex.	
Large VSD with bidirectional shunt + pulmonary hypertension.	•	Cyanosis.
•	Quiet praecordium.
•	No PSM.
•	P2 loud.
•	No MDM.	

5.	Natural history

a.	Spontaneous closure:

i.	variable rate.

ii.	as high as 60% by 5th year of life.

iii.	greatest number closed by 1 year, some by 5 year, few in adulthood.

iv.	large VSD unlikely to close after 2 years.
b.	Complications:

i.	development of infundibular pulmonary stenosis to prevent too much blood from entering the lungs.

ii.	progressive aortic incompetence when one leaflet of the aortic valve prolapses into defect below valve.

iii.	subacute bacterial endocarditis: 30 – 40% mortality.

iv.	recurrent chest infection.

v.	Eisenmenger’s syndrome developing in adolescence due to rise in pulmonary vascular resistance leading to appearance of a right to left shunt with cyanosis.

vi.	congestive cardiac failure.

c.	Death:

i.	VSD die in infancy due to CCF or recurrent bronchopneumonia.

ii.	3% of VSD die later 1st year.

iii.	90% of death occur in infancy.

6.	Differentials

a.	PDA with pulmonary hypertension.

b.	AVSD.

c.	Infundibular pulmonary stenosis.

d.	Truncus arteriosus.

7.	Management

a.	Treatment of cardiac failure.

b.	Echocardiography and cardiac catheterization:

i.	to establish diagnosis.

ii.	determine severity.

iii.	explore and confirm associated lesions.

iv.	if pulmonary flow:systemic flow > 2:1, then operate.

c.	Pulmonary artery banding in infancy: Dammann-Muffler operation to decrease blood flow to lungs by 50%.

d.	Patch closure of VSD:

i.	done at 2 years.

ii.	surgery after body weight is greater than 10kg.

e.	SBE prophylaxis.

Atrial Septal Defect

1.	Classification

a.	Secundum defects: found in the fossa ovale.

b.	Primum defects: low in the atrial septum and abut on the atrioventricular valves, which are abnormal and often incompetent.

2.	Symptoms

a.	Generally asymptomatic in childhood.

b.	Not detected until 5 years of age.

c.	Severity of lesion depends on:

i.	site of defect.

ii.	pressure gradient across defect.

d.	Large defect may present early with easy tiring, dyspnoea and congestive cardiac failure.

3.	Signs

a.	Fixed and wide splitting of soft S2.

b.	ESM at pulmonary area due to high pulmonary flow.

c.	Soft MDM at lower end of sternum, secondary to increased tricuspid flow.

d.	Palpable parasternal heave.

4.	Radiology

a.	Right heart enlargement.

b.	Plethoric lung fields.

c.	Prominent pulmonary artery with small aorta.

5.	ECG

a.	Right axis deviation.

b.	Right bundle branch block.

c.	Right ventricular hypertrophy.

d.	Atrial arrhythmias.

6.	Associated defect

a.	Partial anomalous pulmonary-venous drainage usually with sinus venous which make ASD larger.

b.	Mitral valve prolapse.

c.	AVSD.

d.	Marfan syndrome.

7.	Complications

a.	Congestive heart failure.

b.	Recurrent chest infection.

c.	Pulmonary hypertension.

d.	SBE.

e.	Paradoxical emboli: where emboli from right side of heart enters systemic circulation via ASD.

f.	Atrial fibrillation and flutter.

8.	Management

a.	Cardiac catheterization only when pulmonary hypertension is present.

b.	Indication of operation:

i.	symptomatic large heart with large shunt.

ii.	elevated pulmonary vascular resistance.

c.	Defect usually closed by direct suture, but may require insertion of a patch or a self-expanding ‘double umbrella device placed in the defect.

d.	Most require operation due to relatively safety of operation and possible complications if no operation is done.

9.	Differentials

a.	Innocent murmur.

b.	Mild pulmonary stenosis.

c.	Partial AVSD.

d.	Aortic stenosis.

Atrioventricular Septal Defect

1.	Anatomy

a.	AV septum is the septum between the right atrium and the left ventricle.

b.	AV septum consists of:

i.	anterior membranous part.

ii.	posterior muscular part.

c.	Shunting is from left ventricle to right atrium.

d.	Incomplete AVSD:

i.	includes a group of atrial septal defects low in thea trial septum which abut on the atrioventricular valves and may involve the upper part of the ventricular septum.

ii.	when the ventricular septum is intact only an atrial communication is present – ‘ostium primum ASD’ associated with malformations of the mitral and tricuspid valves which are often incompetent.

e.	Complete AVSD: commonly associated with Down’s syndrome.

2.	Symptoms

a.	Early onset dyspnoea.

b.	Easy tiring.

c.	Feeding problems.

d.	Failure to thrive.

e.	Chest infections.

f.	Cardiac failure.

g.	Mild or no cyanosis.

3.	Signs

a.	Split S2 with loud P2.

b.	ESM at pulmonary area.

c.	PSM.

d.	MDM at mitral area.

4.	Radiology

a.	Plethoric lung fields.

b.	Right heart enlargement.

c.	Left ventricular hypertrophy.

5.	ECG

a.	Left axis deviation.

b.	Right bundle branch block.

6.	Management

a.	Treatment of cardiac failure in early infancy.

b.	Surgery after cardiac catheterization:

i.	pulmonary artery bands.

ii.	closure of VSD with repair of mitral valve.

Patent ductus arteriosus

1.	Pathology

a.	Failure of the ductus arteriosus to close normally in the newborn period may be due to a congenital abnormality of the ductus or to severe prematurity.

b.	In the small premature infant, delayed closure of the ductus often will occur after a period of weeks or months.

2.	Symptoms such as failure to thrive, dypsnoea and recurrent chest infections are similar to those of a large VSD.

3.	Signs

a.	Patients with a small PDA frequently remain asymptomatic.

b.	Continuous machinery murmur audible at the upper left sternal border.

c.	In the presence of a large ductus, collapsing pulses are frequently apparent.

d.	The apex may be displaced and forceful.

e.	Presence of an apical mid-diastolic murmur.

4.	Differentials

a.	Venous hum.

b.	VSD with AR.

5.	Management

a.	In symptomatic premature infants, specific medical treatment with indomethacin, which inhibits prostaglandin synthesis, may be effective in promoting ductal constriction.

b.	However, drug treatment is not effective in mature infants with a persistent ductus and in such patients, surgical intervention to close the ductus is indicated.

c.	This should be carried out at an early stage in symptomatic patients but may be delayed until the second year of life.

d.	In such infants surgery is indicated to eliminate the risk of infective endocarditis.

e.	‘Device closure’ by introduction of one or more embolization ‘coils’ or by placement of a ‘double umbrella device’ via a cardiac catheter.

Pulmonary stenosis

1.	Classification

a.	Valvular: 90% bicuspid / tricuspid.

b.	Subvalvular: 10% usually with Tetralogy of Fallot.

c.	Supravalvular: includes peripheral arterial stenosis, e.g. in congenital rubella syndrome.

2.	May be asymptomatic, dyspnoeic or rarely cyanosis.

3.	Signs

a.	Parasternal heave.

b.	ESM best heard at pulmonary area and radiating through to the back and neck.

c.	Thrill at suprasternal notch.

d.	Ejection click at left sternal border: louder during expiration and fades on inspiration.

e.	S2 split with soft P2.

4.	Differentials of ESM

a.	ASD.

b.	Innocent murmur.

c.	MVP.

5.	Differentials of thrill

a.	ASD.

b.	PDA.

c.	Coarctation or aorta.

6.	Radiology

a.	Normal heart size.

b.	Prominent pulmonary artery: abnormal convexity on the upper left heart border just below the aortic knuckle. 

7.	Prognosis

a.	Mild pulmonary stenosis is a benign condition and is often not progressive.

b.	More severe pulmonary stenosis leads eventually to effort intolerance, angina on exertion and cardiac failure.

c.	Rarely, severe pulmonary stenosis may be present in early infancy with cyanosis due to right to left shunting through the foramen ovale or an associated ASD.

8.	Management

a.	Surgical valvotomy.

b.	Inflation of a balloon in the valve orifice to separate the fused commissures. 

Coarctation of aorta

1.	Pathology

a.	Narrowing of aorta, most commonly around origin of subclavian artery.

b.	A discrete stricture is present in the distal part of the aortic arch close to the site of the ductus arteriosus.

2.	Associated with:

a.	PDA.

b.	Bicuspid aortic valve.

c.	Aneurysm of circle of Willis.

d.	Subaortic stenosis.

3.	Types

a.	Functional PDA

b.	Non-functional PDA

4.	Symptoms

a.	Development of severe cardiac failure in the newborn period, often in the second or third week of life.

b.	Presentation may be delayed until late in childhood or adolescence.

5.	Signs

a.	Diminished or absent femoral pulses.

b.	Radiofemoral delay, commonly right only.

c.	Higher upper limb pressure than lower limb pressure by 20 mmHg.

6.	Non-functional PDA Coarctation of Aorta

a.	Blood supply to lower body via collaterals:

i.	internal mammary artery to inferior epigastric artery.

ii.	anastomosis at shoulder girdle.

iii.	superior intercostal artery to 1st intercostal artery.

b.	Symptoms:

i.	asymptomatic.

ii.	headache, dizziness, tinnitus, epistaxis, palpitations and insomnia.

iii.	intermittent claudication, delayed wound healing in lower limb.

c.	Signs:

i.	prominent carotid pulse.

ii.	visible / palpable collaterals in interscapular region.

iii.	loud ESM at aortic area radiating to neck and mitral area.

7.	Radiology

a.	Cardiomegaly.

b.	Pulmonary congestion.

c.	Abnormal aortic knuckle.

d.	Rib notching due to presence of enlarged intercostal arteries. 

8.	Complications

a.	Left ventricular failure.

b.	Aortic dissection.

c.	Subarachnoid haemorrhage due to ruptured berry aneurysm.

9.	Treatment

a.	Infuse prostaglandins E1.

b.	Treat heart failure.

c.	Surgery if symptomatic, re-stenosis. 

Tetralogy of Fallot

1.	Components

a.	VSD.

b.	Pulmonary stenosis.

c.	Right ventricular hypertrophy.

d.	Overriding aorta.

2.	Pathology

a.	Important lesions are pulmonary stenosis and VSD.

b.	Presence of severe pulmonary stenosis associated with infundibular muscular obstruction with valvar hypoplasia and commissure fusion leads to elevation of right ventricular pressure.

c.	In most patients, the systolic pressure in the left and right ventricles is equal, but the marked resistance to ejection into the pulmonary circulation, due to the stenosis, produces right to left shunting into the aorta.

3.	Symptoms

a.	Cyanosis appears gradually during the early months of life or rarely in later childhood and is more obvious on crying or on exertion.

b.	Hypoxic spells:

i.	development of intermittent episodes of severe hypoxia and cyanosis.

ii.	they may appear spontaneously or precipitated by stress or exercise.

iii.	loss of consciousness may occur.

c.	Failure to thrive.

d.	Reduced exercise tolerance: children often adopt a squatting posture at regular intervals during exertion.

4.	Signs

a.	Single loud S2.

b.	ESM along left sternal edge and in pulmonary area and radiates through to the back: the softer the murmur, the more severe the PS.

5.	Pink Fallot

a.	A less severe form, lesions not severe enough to cause signs.

b.	Left to right shunting.

c.	Blood oxygen saturation in range of 92% with no cyanosis.

6.	Course and prognosis

a.	Cyanosis generally progresses gradually with diminishing exercise tolerance, finger clubbing and in severe cases, growth retardation.

b.	Development of cardiac failure is unusual, but the severe cyanosis leads to extreme compensatory polycythaemia and cerebral thromboembolic complications.

7.	Complications

a.	Cerebral thrombosis due to increase in blood viscosity.

b.	Brain abscess normally due to embolization.

c.	SBE.

d.	Hypoxic spells.

e.	Relative anaemia.

f.	Bleeding tendency: thrombocytopenia and prolonged PTT.

g.	Hyperuricacemia: may cause acute renal failure.

8.	Differentials

a.	Small VSD.

b.	Tricuspid atresia.

9.	Associated lesions

a.	Right sided aortic arch (25%).

b.	Absent pulmonary or dysplastic valve (5%).

c.	Absent pulmonary arterial collateral circulation (5%).

d.	ASD.

e.	Pulmonary atresia.

f.	AVSD.

10.	Radiology

a.	Normal, small or slightly enlarged heart or right ventricle.

b.	Large aorta, stenosis is usually infundibular.

c.	Diminished vascularity, oliguric lung fields.

11.	ECG

a.	RAD.

b.	RVH.

c.	Prolonged ventricular complex in older children.

12.	Management

a.	Prophylactic propranolol: to clamp down sympathetic discharge to the heart and prevent cyanotic attack.

b.	Blalock – Taussic operation: creating a communication between the aorta and a pulmonary artery to increase pulmonary blood flow.

c.	Total correction:

i.	usually done when child is 3 – 4 years old.

ii.	mortality: 5 – 10%.

iii.	close VSD.

iv.	ligate PDA.

v.	open PS.

d.	Conservative:

i.	prophylaxis against SBE.

ii.	dyspnoea and cyanosis: adopt knee-chest position and gives oxygen or morphine.

iii.	correction of relative anaemia with Fe tablets.

13.	Case scenarios

a.	The management of choice is surgery when:

i.	child is old enough: > 2 years old.

ii.	pulmonary artery is of sufficient size (limiting factor).

b.	The timing of this procedure depends on the age of presentation and severity of disease.

c.	Severe FT in neonate / infant:

i.	provide immediate relief by increasing pulmonary blood flow.

ii.	IV PG E infusion in neonates to maintain patency of DA to provide pulmonary blood flow.

iii.	BT shunt to link up subclavian artery to ipsilateral branch of pulmonary artery.

d.	Stable FT in neonate / infant: while awaiting for corrective surgery, conservative medical treatment is advisable.

e.	FT in older children: total corrective surgery.

Transposition of great arteries

1.	Definition

a.	Atrial situs solitus.

b.	AV concordant.

c.	Ventriculoarterial disconcordant.

d.	Venoatrial concordant.

2.	Pathology

a.	The aorta and pulmonary arteries arise from the incorrect ventricles.

b.	Systemic venous blood is directed through from the right side of the heart back into the aorta and pulmonary venous blood through the left side of the heart and back into the pulmonary circulation.

c.	Survival is dependent on transfer of blood across from each circuit into the other via a foramen ovale, ductus arteriosus or a septal defect.

d.	Affected infants generally survive for several days or even weeks due to shunting through the foramen ovale, but few live longer than a month without help.

3.	Associated problems

a.	PDA.

b.	VSD.

c.	Left ventricle outflow tract obstruction.

4.	Symptoms

a.	Cyanosis is present from the early hours of life and usually progresses gradually over the next few days.

b.	Metabolic acidosis also may develop if the situation persists untreated due to the tissue hypoxia.

c.	Apart from the cyanosis the infant may appear completely normal.

5.	Signs

a.	Forceful right ventricular impulse at the left sternal edge.

b.	Narrowly split / single S2.

c.	Soft / absent systolic murmur.

d.	Signs of pulmonary hypertension / congestive heart failure.

6.	Differentials

a.	Respiratory distress syndrome.

b.	Persistent fetal circulation.

c.	Neonatal polyasplenia.

d.	Pulmonary atresia.

e.	Tricuspid atresia.

f.	Truncus arteriosus.

g.	Ebstein anomaly.

h.	Hypoplastic left heart.

7.	Treatment

a.	Cardiac catheterization is performed as an emergency procedure and a catheter with an inflatable balloon at the tip is passed into the left atrium via the foramen ovale.

b.	After inflation of the balloon, the catheter is withdrawn with force into the right atrium producing a tear in the atrial septum and hence creating an atrial septal defect.

c.	This allows more effective interatrial shunting with amelioration of the cyanosis and hypoxia.

8.	Surgery

a.	After successful balloon septostomy most infants will manage comfortably for many weeks or months.

b.	Surgical correction is now performed by transferring the pulmonary artery and the aorta back to their appropriate ventricles.

c.	This needs to be performed in early infancy, usually the first month of life, before the left ventricle has adapted to feeding the low pressure circulation.

d.	Mustard’s operation: wait till infant is 3 – 6 months old and then rerouting blood at atrial level by insertion of a complex intra-atrial patch or baffle.

e.	Senning’s operation: repositioning the patient’s own atrial septum and infolding of part of the right atrium. 

9.	Corrected TGA

a.	Physiological correction (ventricle inversion).

b.	Anatomical and radiological transposition tell by:

i.	mitral / tricuspid valve.

ii.	incompetence of left AV valve.

iii.	subvalvular AS.

c.	Prone to arrhythmias.

Persistent truncus arteriosus

1.	Pathology

a.	A rare defect associated with presence of a single artery which branches shortly after arising from the heart to give rise to the pulmonary artery and aorta.

b.	The truncal valve usually sits astride a large VSD and receives blood from both right and left ventricles.

c.	Pulmonary artery may be rudimentary and blood flow to lungs will be via bronchial artery.

2.	Symptoms

a.	Central cyanosis: polycythaemia, clubbing of fingers and toes.

b.	Breathlessness of exertion, fatigue.

3.	Signs

a.	Poor physical growth.

b.	S2: loud, distinct and always single.

c.	Systolic murmur / thrill at base of heart.

4.	Radiology

a.	Plethoric lung fields.

b.	Cardiomegaly.

c.	Absence of pulmonary artery – concavity / vascular shadow of ventricle.

d.	Enlarged supra-cardiac ‘aortic’ shadow.

5.	Treatment

a.	Surgical correction in early infancy.

b.	The pulmonary artery is separated from the truncus and after closure of the VSD leaving the aorta arising from the left ventricle a valved conduit is placed to connect the right ventricle to the pulmonary arteries.

Ebstein Anomaly

1.	Pathology

a.	Downward displacement of a part of tricuspid valve into right ventricle.

b.	The posterior and medial cusps arise from the wall of the right ventricle instead of the annulus fibrosus resulting in downward displacement of right ventricle.

c.	May be associated with ASD.

2.	Symptoms

a.	Breathlessness on exertion and fatigue.

b.	Central cyanosis during attacks of paroxysmal tachycardia.

c.	Development of CCF.

3.	Signs

a.	Weak peripheral pulses.

b.	Triple rhythm.

4.	Radiology

a.	Oligemic lung fields.

b.	Gross cardiomegaly, enlarged right atrium – waterbag appearance (differential is pericardial effusion).

5.	ECG

a.	Right atrial deviation.

b.	Pulmonary pulmonale.

c.	Frequently with partial / complete RBBB.

6.	Treatment: usually arrhythmia control. 

Tricuspid atresia

1.	Pathology

a.	The tricuspid valve is blocked completely and there is no communication between the right atrium and ventricle.

b.	Systemic venous blood passes via the foramen ovale or an ASD into the left side of the heart and at ventricular or arterial level a left to right shunt exists.

c.	This allows blood to perfuse the pulmonary circulation, usually in reduced amounts.

2.	Signs

a.	Cyanosis develops early.

b.	A systolic murmur is audible along the left sternal border.

3.	ECG

a.	LAD.

b.	RAH.

c.	LVH.

d.	RV hypoplasia.

4.	Treatment

a.	A palliative shunt operation may be performed in infancy.

b.	Later in childhood, reconstructive cardiac surgery to create a wide anastomosis between the right atrium and the pulmonary arteries allowing systemic venous blood to pass directly into the pulmonary circulation (Fontan operation).

Pulmonary atresia

1.	Pathology

a.	The origin of the pulmonary artery from the right ventricle is completely obstructed or absent.

b.	Blood in the right side of the heart passes via an ASD, foramen ovale or VSD into the left ventricle or aorta.

c.	The pulmonary circulation depends on collateral flow from the aorta via a PDA or other collateral channels.

2.	Signs

a.	Cyanosis develops early.

b.	Continuous murmur due to associated PDA.

3.	Treatment

a.	Prostaglandin infusion to maintain patency of the ductus.

b.	Early surgical treatment involves a systemic to pulmonary shunt procedure.

c.	Surgical correction by insertion of a ‘valved conduit’ from the right ventricle into the pulmonary arteries.