Myocardial fibrosis in polymyositis.

Myocardial involvement in polymyositis is commonly suspected in noninvasive studies, but symptomatic cardiac disease is rare. We describe a 27-year-old woman with a 6 year history of severe polymyositis and persistent elevation of creatine phosphokinase-MB isoenzyme who suddenly developed congestive heart failure and bradycardia-tachycardia syndrome. Autopsy revealed severe myocardial fibrosis without inflammatory cell infiltrates concomitant to active polymyositis of the skeletal muscles despite intensive longterm immunosuppressive therapy.