Adult Congenital Heart Disease: ASD, PFO, Coarctation & Eisenmenger

Atrial-level shunts: ASD and PFO

Types of ASD. Secundum defects sit at the fossa ovalis, make up most ASDs, and are the shunt most often first found in adults. Primum defects belong to the endocardial cushion (AV septal) spectrum, cluster with Down syndrome, and bring a cleft mitral valve and left axis deviation. Sinus venosus defects lie near the SVC, travel with partial anomalous pulmonary venous return, and need surgery.

Findings. Atrial left-to-right flow volume-loads the RA, RV and pulmonary arteries. Patients present around 30–40 with exertional dyspnea, fatigue, AF or flutter, paradoxical embolism, right heart failure or pulmonary hypertension. The S2 is widely and fixedly split because the shunt evens out respiratory swings in RV filling; the systolic murmur at the left upper sternal border comes from increased pulmonic flow, not the defect. ECG: incomplete RBBB with right axis deviation; echo: RA and RV enlargement.

Closure. Close an ASD when the right heart is enlarged with Qp:Qs ≥1.5, with or without symptoms: a percutaneous device for secundum defects with adequate rims on TEE, surgery for primum and sinus venosus defects. Closure is contraindicated once pulmonary vascular resistance is prohibitive or the shunt has reversed. Late closure still helps symptoms, but atrial arrhythmias may persist.

Patent foramen ovale. Unfused septum primum and secundum leave a flap in about 25% of adults. It opens whenever RA pressure exceeds LA pressure (Valsalva, cough, straining), permitting paradoxical embolism and decompression illness in divers. On an agitated-saline (bubble) echo, bubbles in the LA within 3 cardiac cycles indicate an intracardiac shunt; bubbles after about 3–5 beats suggest an intrapulmonary shunt such as a pulmonary AVM. TEE is most accurate.

When to close a PFO. Closure plus long-term antiplatelet therapy lowers recurrence in patients aged 18–60 with a nonlacunar, embolic-appearing stroke and no other cause after full workup (vessel imaging, echo, prolonged rhythm monitoring for AF), especially with an atrial septal aneurysm or large shunt. The RoPE score estimates causality — younger age, no vascular risk factors and a cortical infarct raise it. An incidental PFO needs no treatment; a coexisting DVT is anticoagulated in its own right.

Ventricular and arterial shunts: VSD and PDA

VSD. The most common congenital defect at birth, usually perimembranous, with a harsh holosystolic murmur at the left lower sternal border that is loudest when the hole is small and restrictive; many muscular VSDs close in childhood. Small adult VSDs mainly carry endocarditis risk and, when perimembranous or outlet, aortic regurgitation from cusp prolapse. Close a VSD when the LV is dilated with Qp:Qs ≥1.5 and pulmonary pressures are acceptable. Large unrepaired defects progress to Eisenmenger physiology; a murmur that fades as cyanosis appears signals reversal, not healing.

PDA. Linked to prematurity and congenital rubella, a PDA gives a continuous machinery murmur below the left clavicle, bounding pulses and a wide pulse pressure. A moderate or large duct overloads the LA and LV and is closed with a transcatheter device. If flow reverses, deoxygenated blood enters the aorta beyond the left subclavian artery: cyanotic, clubbed toes with pink fingers (differential cyanosis).

Coarctation and bicuspid aortic valve

Coarctation. The narrowing usually lies just distal to the left subclavian artery near the ductus. Leg systolic pressure normally exceeds arm pressure; in coarctation the arms are hypertensive (headache, epistaxis) while femoral pulses are weak and delayed and the legs are cool, with exertional claudication. A systolic murmur is heard over the left interscapular back. The chest film shows inferior rib notching from intercostal collaterals, sparing ribs 1–2 (their intercostals do not arise from the aorta), and a figure-3 contour from pre- and poststenotic dilation; barium swallow shows the reverse-3 (E) sign. CT or MR angiography confirms the lesion and plans repair (echo in children).

Associations and treatment. About half or more of patients have a bicuspid aortic valve; others have Turner syndrome (45,X), berry aneurysms of the circle of Willis or aortic dissection. Intervene for a peak gradient ≥20 mmHg, or for significant narrowing with collaterals and hypertension: balloon angioplasty with stenting in most adults, or surgery. Follow-up is lifelong because hypertension often persists and recoarctation or aneurysm can develop.

Bicuspid aortic valve. The most common congenital heart anomaly (about 1–2% of people, more often male) gives an ejection click, calcific aortic stenosis one to two decades earlier than a trileaflet valve, aortic regurgitation and endocarditis. An intrinsic aortopathy dilates the ascending aorta independent of valve function and can progress after valve replacement, so the aorta is imaged serially and replaced at about 5.5 cm (earlier with risk factors or during valve surgery). First-degree relatives are screened with echocardiography.

Eisenmenger syndrome and pregnancy

Pathophysiology. Pulmonary overcirculation remodels the arterioles until pulmonary vascular resistance exceeds systemic resistance and the shunt reverses — fastest with a large VSD or PDA, slowest with an ASD. Late cyanosis, clubbing, a loud P2, an RV heave and secondary erythrocytosis follow, while the original murmur softens or disappears. The vascular disease is fixed, so defect closure is contraindicated.

Management. Pulmonary vasodilators (bosentan, sildenafil) improve exercise capacity. Avoid dehydration, high altitude and abrupt vasodilation, and filter IV lines against paradoxical air embolism. Phlebotomy is reserved for symptomatic hyperviscosity; routine phlebotomy causes iron deficiency. Heart-lung transplantation is the last resort.

Pregnancy. The fixed pulmonary bed cannot accommodate pregnancy, falling systemic resistance increases right-to-left shunting, and thrombosis and postpartum collapse are common, with historical maternal mortality of about 30–50%. Counsel against pregnancy, provide effective estrogen-free contraception (progestin-only or copper methods), and offer termination. Comparable risk applies to pulmonary arterial hypertension of any cause, LVEF below 30%, severe mitral stenosis, severe symptomatic aortic stenosis, and Marfan syndrome with an aorta above 45 mm.

Repaired tetralogy and Ebstein anomaly

Tetralogy of Fallot after repair. Tetralogy (VSD, overriding aorta, RV outflow obstruction, RV hypertrophy; associated with 22q11 deletion) is repaired in infancy, often with a transannular patch that leaves chronic severe pulmonary regurgitation. The RV dilates silently for decades before exercise intolerance, right heart failure, atrial arrhythmias, VT and sudden death appear. RBBB is almost universal after repair, and a QRS ≥180 ms flags VT risk. Cardiac MRI tracks RV volumes; pulmonary valve replacement (surgical or transcatheter) is timed before the RV fails, and an ICD is placed for high arrhythmic risk.

Ebstein anomaly. Apical displacement of the septal and posterior tricuspid leaflets atrializes part of the RV, causing tricuspid regurgitation, a huge RA (box-shaped heart on chest film), right heart failure and — through an ASD or PFO — cyanosis. Accessory pathways (WPW) are common and cause SVT. The classic link is maternal lithium, though the absolute risk is lower than once feared. Treatment includes tricuspid repair (cone procedure) and ablation.