Ventricular septal defect

Atrial septal defect is a communication in the interatrial septum causing a left-to-right shunt, often silent until adulthood. It classically produces a fixed split second heart sound and, over time, right heart volume overload, atrial arrhythmias, and pulmonary hypertension; hemodynamically significant defects are closed by device or surgery.

Patent ductus arteriosus is persistence of the fetal ductus connecting the aorta and pulmonary artery, causing a continuous machinery murmur and a left-to-right shunt. In preterm infants it is treated with prostaglandin inhibitors; in others it is closed by transcatheter device or surgery, before pulmonary vascular disease develops.

Eisenmenger syndrome is the end stage of a large uncorrected left-to-right cardiac shunt, in which chronic pulmonary overcirculation causes irreversible pulmonary vascular disease and shunt reversal to right-to-left with cyanosis. The defect can no longer be closed; management is specialized supportive care, pulmonary vasodilators, and avoidance of destabilizing insults.

Mitral regurgitation is systolic backflow from the left ventricle into the left atrium, classified as primary (valve disease) or secondary (ventricular or annular disease). Chronic disease causes volume overload with an apical holosystolic murmur, while acute severe regurgitation causes pulmonary edema; severe primary disease is treated with valve repair or replacement.

Tricuspid regurgitation is systolic backflow from the right ventricle into the right atrium, most often secondary (functional) from right ventricular or annular dilation and pulmonary hypertension. It causes right-sided congestion with a prominent jugular v wave and a systolic murmur that increases on inspiration; management targets the underlying cause and, in selected severe disease, valve intervention.

Hypertrophic cardiomyopathy is an autosomal dominant sarcomere disease causing unexplained left ventricular hypertrophy, often with dynamic left ventricular outflow tract obstruction, and is a leading cause of sudden cardiac death in young people. Diagnosis is by echocardiography or cardiac MRI showing unexplained hypertrophy, and management includes negative inotropes, obstruction relief, and ICD placement for high sudden-death risk.

Ventricular septal rupture is a mechanical complication of myocardial infarction in which necrosis creates a septal defect and an acute left-to-right shunt, causing biventricular failure and cardiogenic shock days after an infarct, with a new harsh holosystolic murmur and thrill. Diagnosis is by echocardiography with a right-heart oxygen step-up, and treatment is stabilization bridging to emergent surgical closure.

Aortic stenosis is obstruction to left ventricular outflow from a narrowed aortic valve, most often calcific degeneration in older adults or a bicentric bicuspid valve earlier in life. Symptoms of angina, syncope, or heart failure mark a poor prognosis, and severe symptomatic disease is treated with valve replacement (surgical or transcatheter).