ACTIVE MYOCARDITIS IN THE SPECTRUM OF ACUTE DILATED CARDIOMYOPATHIES - CLINICAL-FEATURES, HISTOLOGIC CORRELATES, AND CLINICAL OUTCOME

The clinical features and course (average follow-up time, 18 mon.) of 27 patients with acute dilated cardiomyopathy (symptoms for < 6 mo.) who were referred for endomyocardial biopsy were studied. Almost 40% of the patients subsequently had a rise in left ventricular ejection fraction (on average, from 0.21-0.41) and substantial improvement in heart failure; the remainder died or had chonic dilated cardiomyopathy. Biopsy revealed myocarditis in 18 patients and this finding was especially common (89%) in patients who had been ill for < 4 wk. But the biopsy specimen was negative in 4 patients whose clinical features and later course were diagnostic of myocarditis. Nine patients received immunosuppressive drugs and 4 improved.sbd.a rate that did not differ from the rate of spontaneous improvement. Neither the histologic features of the biopsy specimen nor the clinical features at presentation were clearly correlated with subsequent improvement, whether or not immunosuppressive drugs were given. Many cases of unexplained dilated cardiomyopathy result from myocarditis. Definitive histologic confirmation depends on the duration of illness. The efficacy of immunosuppressive treatment must still be established.