Clinical and histopathological profile of sarcoidosis of the heart and acute idiopathic myocarditis. Concepts through a study employing endomyocardial biopsy. II. Myocarditis.

Through an approach employing endomyocardial biopsy, early diagnosis of acute idiopathic myocarditis is possible. The histopathological findings consisted of fragmentation of muscle bundles, degenerative changes with lysis of myocytes and interstitial mononuclear cell infiltration. The cells were irregular in size and shape and contained slightly basophilic cytoplasm or were mixed with small round cells. Early clinical symptoms consisted of flu-like symptoms, i. e., higher fever, myalgia, malaise and arthralgia. Initial ECG changes consisted of complete A-V block in 9, bifascicular block in 3, and intraventricular conduction disturbance in 4 cases. Serial biopsies were performed at the early (0--2 weeks), middle (2--4 weeks), and late stages (more than 4 weeks) in 6 cases. Two of these biopsies were performed in 6 cases and all 3 were performed in one case. The numerous interstitial cell infiltration had almost disappeared by the early stage. At the late stage, either a slight or moderate degree of interstitial fibrosis was observed. These observations coincided well with the improvement of the ECG findings. Characteristic laboratory findings consisted of high LDH, GOT, and serum amylase levels. Varieties of treatments such as temporary cardiac pacing, peritoneal or hemo-dialysis, vasodilator therapy effectively to relieve the grave clinical condition. It is concluded that acute myocarditis may heal with remarkable improvement when the appropriate treatment is applied at the early stage of the disease.