If congenitally bicuspid aortic valve and mitral valve prolapse are excluded, ASD is the most common form of congenital heart disease in adults, constituting approximately 25% of these patients.

Some 65% to 75% of ASDs are ostium secundum type and represent true defects of the atrial septum in the region of the fossa ovalis.

A wide, fixed-split S2 is the hallmark auscultatory feature of ASD.

Because of the reduced life expectancy of patients with uncorrected ASDs, those who have a significant shunt, classically defined as a pulmonary blood flow to systemic flow (Qp:Qs) shunt fraction >1.5 to 1, symptoms, or evidence of right heart enlargement should be offered repair.

VSDs are frequently found in conjunction with other cardiac anomalies, including coarctation of the aorta and PDA.

The majority (˜70%) of VSDs are located in the membranous septum, approximately 20% in the muscular portion of the trabecular septum (muscular VSD), about 5% in the infundibular septum beneath the pulmonary valve (subpulmonary VSD), and about 5% in the inlet septum near the tricuspid valve (atrioventricular canal-type VSD).

The size of the VSD, ventricular pressure, and pulmonary vascular resistance are determinants of hemodynamic significance. If the pulmonary hypertension is severe enough, this can result in reversal of flow, leading to right-to-left shunt and cyanosis (Eisenmenger’s syndrome).

The classic auscultatory finding in a VSD is a holosystolic murmur, the intensity of which depends on the velocity of flow.

Indications for VSD repair include a significant left-to-right shunt (Qp:Qs > 2) with evidence of left ventricular volume overload, or a history of endocarditis.

A contraindication for VSD repair is severe irreversible pulmonary arterial hypertension.

The ductus arteriosus is a fetal structure connecting the proximal descending aorta just distal to the left subclavian artery to the distal main pulmonary artery.

Like ASDs and VSDs, PDA is a shunt lesion that results in left-to-right flow.

Some adults with PDA will develop signs of congestive heart failure from chronic left-to-right shunting.

The classic auscultatory feature of PDA is the harsh continuous murmur at the left upper sternal border. This murmur involves S2 and is decreased in intensity during diastole.

In general, closure of the PDA is recommended for all patients with left atrial and/or left ventricular enlargement, net left-to-right shunting across the PDA, pulmonary vascular disease, or a history of endarteritis.

A contraindication to PDA closure is severe pulmonary hypertension that results in right-to-left shunting across the PDA.

If the PDA is amenable, transcatheter closure using a coil or an Amplatzer ductal occluder (AGA Medical, Golden Valley, MN) is the treatment of choice for adults, with surgery being reserved for very large PDAs.

Aortic coarctation usually presents as a discrete narrowing in the thoracic aorta in the region of the ligamentum arteriosum.

Associated lesions include bicuspid aortic valve in up to 50% of cases, intracranial aneurysms in 10%, and less commonly VSDs.

Young adults classically present upper extremity hypertension with diminished or delayed femoral pulses. Any young patient with hypertension should be evaluated clinically for coarctation by simultaneous palpation of the brachial and femoral pulses to assess for “brachialfemoral delay,” as well as by comparing blood pressures in the right and left upper extremity and one lower extremity.

The classic finding on chest radiography is the “3,” or “reverse E” sign, representing a dilated left subclavian artery above the coarctation and poststenotic aortic dilatation beyond the coarctation.

Untreated patients with aortic coarctation have poor survival, with an estimated mortality of 75% by 46 years of age and median age of death being only 31 years.

Stent implantation for coarctation became a treatment option in the early 1990s and is preferred in adults and adult-size adolescents.

TOF is characterized by pulmonic stenosis, overriding aorta, interventricular communication, and right ventricular hypertrophy, with considerable variability in morphology.

Adult TOF patients will likely present after primary repair. The repaired patient will no longer be cyanotic but can present with a host of other problems that require lifelong follow-up, including pulmonic insufficiency, ventricular tachycardia, atrial arrhythmias, right heart failure, and ascending aortic dilatation.