Normal and abnormal consequences of apoptosis in the human heart.

Knowledge about apoptosis has become essential for understanding many aspects of cardiac structure and function. In the human heart there are major periods of morphogenesis that begin only after birth, and some of these processes recur intermittently for many years. Although the exact mechanisms by which these events are initiated or terminated remain poorly understood, it is clear that their benefits may be mirrored in destructive effects. In this review, selected examples include normal morphogenesis of the cardiac conduction system and the normal postnatal involution of the right ventricle, both of which are mediated by apoptosis. Destructive counterparts include familial heart block ending in fatal arrhythmias, similar results in the long QT syndrome, and the pathogenesis of both Uhl's anomaly and arrhythmogenic right ventricular dysplasia; in each apoptosis is an important factor.