Cardiac sarcoidosis: a potentially treatable form of myocarditis.

A 39-year-old woman had a 2-year history of heart block, which had necessitated pacemaker implantation, and a 6-month history of heart failure. Endomyocardial biopsy specimens initially revealed lymphocytic myocarditis but subsequently showed giant cell myocarditis. She died suddenly, and autopsy disclosed extensive cardiac sarcoidosis with minimal extracardiac involvement. Cardiac sarcoidosis may be difficult to diagnose clinically because the extent of cardiac and the extent of extracardiac involvement tend to be inversely related. Endomyocardial biopsy may be helpful in diagnosing such cases.