Immunosuppressive treatment in myocarditis.

Twenty patients (13 males and seven females) with a biopsy-proven diagnosis of myocarditis underwent a period of treatment with prednisone and azathioprine. The primary objective of the study was the observation of histologic changes which occur during treatment and after treatment withdrawal. The secondary objective was the detection, if any, of changes in left ventricular ejection fraction. Multiple endomyocardial biopsies were obtained and the treatment was adjusted in order to achieve complete disappearance of the myocardial inflammation. The histologic status was improved in all patients, although complete disappearance of the signs of active disease was seen in 15 patients only. Two patients died during the observation period. A clear relationship between histologic status and immunosuppression was established in some patients (50% of all cases showed a worsening after withdrawal from the treatment). An overall improvement of the ejection fraction was observed (from 0.37 +/- 0.14 to 0.46 +/- 0.17), but a direct effect of the treatment on the recovery of ventricular function cannot be stated. In some patients, however, a direct relationship between the histological changes and the changes in ejection fraction was seen. These data suggest that treatment with prednisone and azathioprine may be beneficial in some patients with biopsy-proven myocarditis and depressed ventricular function.