Arrhythmogenic right ventricular dysplasia (ARVD) is a form of cardiomyopathy characterized by fibrofatty infiltration of the right ventricle that leads to cardiac arrhythmias, usually sustained ventricular tachycardia or ventricular fibrillation. ARVD typically becomes recognized in young adults. The authors report a case of an octogenarian in whom third-degree atrioventricular block, low cardiac output syndrome, and failure to capture the pacer stimuli developed. ARVD was diagnosed at autopsy based on fibrofatty replacement of the right ventricle. To date, this case represents the oldest patient ever diagnosed with ARVD reported in the literature.