Cardiac sarcoid: a clinicopathologic study of 84 unselected patients with systemic sarcoidosis.

Although sarcoid may involve the myocardium, there is little information on its incidence or significance. We studied 84 consecutive autopsied patients with sarcoidosis. The patients ranged in age from 18--80 years (average 46 years) and 61% were women; 23 (27%) of them had myocardial granulomas. In eight (35%) these were clinically silent, and in 15 (65%) there was a history of heart failure and/or arrhythmias and conduction defects. Of the 23 patients, only four (17%) had grossly evident, widespread myocardial lesions: three of these four (75%) had documented arrhythmias. All four had sudden, unexpected death at an average age of 36 years; in only two had sarcoid been suspected during life. The other 19 patients (83%) had microscopically evident granulomatous involvement. Of these, eight (42%) had a thythm or conduction disturbance and three (16%) sudden death, although none of those who suffered sudden death had a recognized rhythm or conduction disturbance. Nine (15%) of those without cardiac sarcoidosis had a rhythm or conduction disturbance and eight (13%) suffered a sudden death. The results show that although myocardial involvement occurs in at least 25% of patients with sarcoid, it most often involves a small portion of myocardium and is clinically silent. Since some of the 61 patients in whom myocardial lesions were not identified may still have had small microscopic granulomas, the true incidence of myocardial sarcoid may be even greater than suggested here. Rhythm and conduction disturbances are more common in the cardiac sarcoid group, but the findings suggest that only the small subset of patients with severe, grossly evident myocardial sarcoid are at increased risk for sudden death.