Although arrhythmogenic right ventricular dysplasia (ARVD) is believed to involve primarily the right ventricle, left ventricular abnormalities have also been described. We report a case of ARVD with abnormalities of the sinus node, right atrium and atrioventricular node. The biopsies taken from the right atrium and the right ventricle showed replacement of myocardium by fibrous tissue. The pathologic changes of this disease process may extend into the atrium and atrioventricular node.