Apoptosis in congenital heart disease.

Morphogenesis in the human body is mediated to an important, but not exclusive, extent by apoptosis. That this is true in the heart is illustrated by primary pulmonary hypertension, which includes medial degeneration in both coronary and pulmonary arteries, normal and abnormal postnatal involution of the right ventricle, familial progressive heart block ending in fatal arrhythmias, and the long QT syndrome. Apoptosis occurs in ventricular myocardium, specialized myocytes of the conduction system, endothelium and medial smooth muscle of small arteries, cardiac nerves and ganglia and fibroblasts. The normal onset, duration and termination of apoptosis act beneficially. If apoptosis fails to occur or is too long continued, the result is harmful. Little is known of the signals controlling apoptosis in the human heart. Future research into these questions may radically change many of our present concepts of congenital heart disease.