Recurrent myocarditis of unknown etiology.

A 42-year-old man presented with dyspnea and common cold-like symptoms. His electrocardiogram showed complete atrioventricular block and chest radiography revealed cardiomegaly and pulmonary congestion. He had a history of three recurrences of active myocarditis proven by endomyocardial biopsy over a 14-year period. Viral studies showed no evidence of recent infection, and no medications had been taken prior to this episode. This myocarditis was suggested as an unknown etiology.