[Two autopsied cases of arrhythmogenic right ventricular dysplasia]

Autopsy studies of arrhythmogenic right ventricular dysplasia (ARVD) have rarely been reported, and its etiology remains unknown. The present report describes a detailed histopathological study of two autopsied cases of ARVD. Case 1: This 21-year-old man experienced palpitation accompanied by syncope. He died after ventricular tachycardia of right ventricular origin. The heart weighed 365 g and the right ventricular cavity was markedly dilated. The distribution of fatty tissue was roughly limited to the middle layer of the free wall, replacing the myocardium with fatty degeneration. Medial hyperplasia of the small arteries within the fatty tissue was also observed. Fibroelastosis was observed in the left ventricular endocardium. In the conduction system, fatty tissue was found in the sinus node. In addition, medial hypoplasia was observed in the pulmonary arteries. Case 2: This 32-year-old man who had had an arrhythmia for 10 years died of ventricular tachycardia of right ventricular origin. His older brother also died of heart disease. His heart weighed 515 g and both the right and left ventricles were dilated. Fatty tissue, unlike that in Case 1, was shown to markedly infiltrate from the epicardium into both the right and left ventricular walls. In the right ventricular wall, muscle layers disappeared in some portions. In the conduction system, fatty tissue was observed in the sinus node. Although ARVD may be considered a syndromic entity, individual cases are different in terms of pathological morphology, with possible variations in the etiology and pathogenesis.