- Atrial Septal Defect (Asd)
- Ventricular Septal Defect (Vsd)
- Patent Ductus Arteriosus (Pda)
- Progression to Pht
Most common is ostium secundum ASD, located at mid interatrial septum. Ostium primum ASDs (e.g., typical of Down syndrome) appear at lower atrial septum and are associated with abnormal development of atrioventricular (AV) valves, especially a cleft appearance of the mitral valve. Sinus venosus type defects do not actually involve the atrial septum, but rather represent a defect localized between a right pulmonary vein and the junction of the superior vena cava or inferior vena cava with the right atrium (RA). Physiologically such defects mimic ASDs.
When discovered in adulthood, usually asymptomatic until third or fourth decades, when exercise intolerance, dyspnea, and palpitations may occur. Onset of symptoms may be associated with development of pulmonary hypertension (PHT) (see below).
Wide, fixed splitting of S2, systolic murmur from flow across pulmonic valve, possible diastolic flow rumble across tricuspid valve, prominent jugular venous v wave.
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.
Increased pulmonary vascular markings, prominence of RA, RV, and main pulmonary artery (LA enlargement not usually present).
| TREATMENT | ||
Atrial Septal DefectIn the absence of contraindications an ASD with a significant pulmonary-to-systemic flow (Qp/Qs) ratio (≥1.5:1.0) with right heart enlargement should be considered for surgical or percutaneous transcatheter closure. Closure is usually contraindicated with significant PHT and is not undertaken for small defects with trivial left-to-right shunt flow. |
Ventricular Septal Defect (Vsd) 
Most common congenital abnormality at birth but many close spontaneously during childhood. Symptoms relate to size of the defect and pulmonary vascular resistance.
CHF may develop in infancy. Adults may be asymptomatic or develop fatigue and reduced exercise tolerance. Pts are susceptible to endocarditis.
Holosystolic murmur at lower left sternal border, which may be accompanied by a palpable thrill, loud P2; diastolic flow murmur across mitral valve.
| TREATMENT | ||
Ventricular Septal DefectPercutaneous or surgical closure is indicated for pts with symptoms, or with volume overload, in the absence of irreversible pulmonary vascular disease; closure is also reasonable if Qp/Qs >1.5:1 and pulmonary artery pressure <2/3 systemic pressure and pulmonary vascular resistance <2/3 systemic resistance. |
Patent Ductus Arteriosus (Pda)
Abnormal communication between the descending aorta and pulmonary artery; associated with birth at high altitudes and maternal rubella.
Hyperactive LV impulse; loud continuous “machinery” murmur below the left clavicle. If PHT develops, diastolic component of the murmur may disappear.
Increased pulmonary vascular markings: enlarged main pulmonary artery, LV, ascending aorta; occasionally, calcification of ductus.
| TREATMENT | ||
Patent Ductus ArteriosusIn absence of PHT, PDA should be surgically ligated or divided to prevent infective endocarditis, LV dysfunction, and PHT. Transcatheter device closure is frequently possible. |
Pts with large, uncorrected left-to-right shunts (e.g., ASD, VSD, or PDA) may develop progressive, irreversible PHT with reverse shunting of desaturated 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 (see Chap. 129 Pulmonary Hypertension) and consideration of lung transplant with repair of the cardiac defect, or heart-lung transplantation. Pregnancy is contraindicated because of high mortality.