ACYANOTIC CONGENITAL HEART LESIONS WITH LEFT-TO-RIGHT SHUNT
ATRIAL SEPTAL DEFECT (ASD)
Most common is ostium secundum ASD, located at mid interatrial septum. Sinus venosus type ASD involves the high atrial septum and may be associated with anomalous pulmonary venous drainage to the right heart. Ostium primum ASDs (e.g., typical of Down syndrome) appear at lower atrial septum, adjacent to atrioventricular (AV) valves.
History
Usually asymptomatic until third or fourth decades, when exertional dyspnea, fatigue, and palpitations may occur. Onset of symptoms may be associated with development of pulmonary hypertension (see below).
Physical Examination
Prominent right ventricular (RV) impulse, wide fixed splitting of S2, systolic murmur from flow across pulmonic valve, diastolic flow rumble across tricuspid valve, prominent jugular venous v wave.
ECG
Incomplete RBBB (rSR’ in right precordial leads) common. Left axis deviation frequently present with ostium primum defect. Ectopic atrial pacemaker or first degree AV block occur in sinus venosus defects.
CXR
Increased pulmonary vascular markings, prominence of right atrium (RA), RV, and main pulmonary artery (LA enlargement not usually present).
Echocardiogram
RA, RV, and pulmonary artery enlargement; Doppler shows abnormal turbulent transatrial flow. Echo contrast (agitated saline injection into peripheral systemic vein) may visualize transatrial shunt. Transesophageal echo usually diagnostic if transthoracic echo is ambiguous.
TREATMENT Atrial Septal Defect
In the absence of contraindications an ASD with pulmonary-to-systemic flow ratio (PF:SF) >2.0:1.0 should be repaired surgically or by percutaneous transcatheter closure. Surgery is contraindicated with significant pulmonary hypertension and PF:SF <1.2:1.0. Medical management includes antiarrhythmic therapy for associated atrial fibrillation or supraventricular tachycardia (Chap. 132) and standard therapy for symptoms of heart failure (Chap. 133).
VENTRICULAR SEPTAL DEFECT (VSD)
Congenital VSDs may close spontaneously during childhood. Symptoms relate to size of the defect and pulmonary vascular resistance.
History
CHF may develop in infancy. Adults may be asymptomatic or develop fatigue and reduced exercise tolerance.
Physical Examination
Systolic thrill and holosystolic murmur at lower left sternal border, loud P2, S3; diastolic flow murmur across mitral valve.
ECG
Normal with small defects. Large shunts result in LA and LV enlargement.
CXR
Enlargement of main pulmonary artery, LA, and LV, with increased pulmonary vascular markings.
Echocardiogram
LA and LV enlargement; defect may be directly visualized. Color Doppler demonstrates flow across the defect.
TREATMENT Ventricular Septal Defect
Fatigue and mild dyspnea are treated with diuretics and afterload reduction (Chap. 133). Surgical closure is indicated if PF:SF >1.5:1 in absence of very high pulmonary vascular resistance.
PATENT DUCTUS ARTERIOSUS (PDA)
Abnormal communication between the descending aorta and pulmonary artery; associated with birth at high altitudes and maternal rubella.
History
Asymptomatic or fatigue and dyspnea on exertion.
Physical Examination
Hyperactive LV impulse; loud continuous “machinery” murmur at upper left sternal border. If pulmonary hypertension develops, diastolic component of the murmur may disappear.
ECG
LV hypertrophy is common; RV hypertrophy if pulmonary hypertension develops.
CXR
Increased pulmonary vascular markings: enlarged main pulmonary artery, LV, ascending aorta; occasionally, calcification of ductus.
Echocardiography
Hyperdynamic, enlarged LV; the PDA can often be visualized on two-dimensional echo; Doppler demonstrates abnormal flow through it.
TREATMENT Patent Ductus Arteriosus
In absence of pulmonary hypertension, PDA should be surgically ligated or divided to prevent infective endocarditis, LV dysfunction, and pulmonary hypertension. Transcatheter device closure is frequently possible.
PROGRESSION TO PULMONARY HYPERTENSION (PHT)
Pts with large, uncorrected left-to-right shunts (e.g., ASD, VSD, or PDA) may develop progressive, irreversible PHT with reverse shunting of desatu-rated blood into the arterial circulation (right-to-left direction), resulting in Eisenmenger syndrome. Fatigue, lightheadedness, and chest pain due to RV ischemia are common, accompanied by cyanosis, clubbing of digits, loud P2, murmur of pulmonary valve regurgitation, and signs of RV failure. ECG and echocardiogram show RV hypertrophy. Therapeutic options are limited and include pulmonary artery vasodilators and consideration of single lung transplant with repair of the cardiac defect, or heart-lung transplantation.
ACYANOTIC CONGENITAL HEART LESIONS WITHOUT A SHUNT
PULMONIC STENOSIS (PS)
A transpulmonary valve gradient < 30 mmHg indicates mild PS, 30–50 mmHg is moderate PS, and >50 mmHg is considered severe PS. Mild to moderate PS rarely causes symptoms, and progression tends not to occur. Pts with higher gradients may manifest dyspnea, fatigue, light-headedness, chest pain (RV ischemia).
Physical Examination
Jugular venous distention with prominent a wave, RV parasternal impulse, wide splitting of S2 with soft P2, ejection click followed by “diamond-shaped” systolic murmur at upper left sternal border, right-sided S4.
ECG
Normal in mild PS; RA and RV enlargement in advanced PS.
CXR
Often shows poststenotic dilatation of the pulmonary artery and RV enlargement.
Echocardiography
RV hypertrophy and systolic “doming” of the pulmonic valve. Doppler accurately measures transvalvular gradient.
TREATMENT Pulmonic Stenosis
Symptomatic or severe stenosis requires balloon valvuloplasty or surgical correction.
CONGENITALLY BICUSPID AORTIC VALVE
One of the most common congenital heart malformations (up to 1.4% of the population); rarely results in childhood aortic stenosis (AS), but is a cause of AS and/or regurgitation later in life. May go undetected in early life or suspected by the presence of a systolic ejection click; often identified during echocardiography that was obtained for another reason. See Chap. 123 for typical history, physical findings, and treatment of subsequent clinical aortic valve disease.
COARCTATION OF THE AORTA
Aortic constriction just distal to the origin of the left subclavian artery is a surgically correctable form of hypertension (Chap. 126). Usually asymptomatic, but may cause headache, fatigue, or claudication of lower extremities. Often accompanied by bicuspid aortic valve.
Physical Examination
Hypertension in upper extremities; delayed femoral pulses with decreased pressure in lower extremities. Pulsatile collateral arteries can be palpated in the intercostal spaces. Systolic (and sometimes also diastolic) murmur is best heard over the mid-upper back at left interscapular space.
ECG
LV hypertrophy.
CXR
Notching of the ribs due to collateral arteries; “figure 3” appearance of distal aortic arch.
Echocardiography
Can delineate site and length of coarctation, and Doppler determines the pressure gradient across it. MR or CT angiography also visualizes the site of coarctation and can identify associated collateral vessel formation.
TREATMENT Coarctation of the Aorta
Surgical correction (or percutaneous transcatheter stent dilation in selected pts), although hypertension may persist. Recoarctation after surgical repair may be amenable to percutaneous balloon dilatation.
COMPLEX CONGENITAL HEART LESIONS
Such lesions are often accompanied by cyanosis. Examples include:
TETRALOGY OF FALLOT
The four main components are (1) malaligned VSD, (2) obstruction to RV outflow, (3) aorta that overrides the VSD, and (4) RV hypertrophy (RVH). Degree of RV outflow obstruction largely determines clinical presentation; when severe, the large right-to-left shunt causes cyanosis and systemic hypoxemia. ECG shows RVH. CXR demonstrates “boot-shaped” heart with prominent RV. Echocardiographydelineates VSD, overriding aorta, and RVH and quantitates degree of RV outflow obstruction.
COMPLETE TRANSPOSITION OF THE GREAT ARTERIES
Accounts for 10% of pts with cyanotic congenital heart disease. Aorta and pulmonary artery arise abnormally from the right and left ventricles respectively, creating two separate parallel circulations; a communication must exist between the two sides (ASD, PDA, or VSD) to sustain life. Development of RV dysfunction and heart failure are common by the third decade. Echocardiography reveals the aberrant anatomy.
EBSTEIN ANOMALY
Abnormal downward placement of tricuspid valve within the RV; tricuspid regurgitation, hypoplasia of RV, and a right-to-left shunt are common. Echocardiography shows apical displacement of tricuspid septal leaflet, abnormal RV size, and quantitates degree of tricuspid regurgitation.
ENDOCARDITIS PROPHYLAXIS IN CONGENITAL HEART DISEASE
American Heart Association 2007 Guidelines recommend antibiotic prophylaxis only in specific pts with congenital heart disease, i.e., those who are to undergo a dental procedure associated with bacteremia who have:
1. Unrepaired cyanotic congenital heart disease (e.g., tetralogy of Fallot)
2. Repaired congenital heart disease with residual defects adjacent to site of a prosthetic patch or transcatheter device
3. A history of complete repair of congenital defects with prosthetic material or a transcatheter device within the previous 6 months.
For a more detailed discussion, see Child JS, Aboulhosn J: Congenital Heart Disease in the Adult, Chap. 236, p. 1920, in HPIM-18.