Whether arrhythmogenic right ventricular dysplasia (ARVD), Uhl's anomaly, and right ventricular outflow tract (RVOT) tachycardia are separate entities is undergoing reevaluation because of new information. Patients with Uhl's anomaly and ARVD have different clinical modes of presentation. The Uhl's anomaly patient frequently has congestive heart failure and presents at an earlier age, whereas a patient with ARVD manifests ventricular arrhythmias in adolescence or adulthood. Nevertheless, the pathogenesis of Uhl's may be caused by the onset of apoptosis (programmed cell death) of the right ventricle that starts in infancy or childhood and is a continuous process, whereas the pathogenesis of ARVD may be similar, but the process of cell death starts in adolescence and can be intermittent. The patient with RVOT tachycardia can have structural disease of the right ventricle more commonly than previously appreciated. It is not clear whether this condition represents a forme fruste of ARVD.