On the basis of newer knowledge from literature in a survey aspects of symptomatology, diagnostics and course of the myocarditis important for practice are represented. According to the frequency of the virus myocarditis is referred to the importance of immunopathogenetic factors for prognosis and course. Own experiences confirm the transition from an acute myocarditis into a chronic cardiomyopathy which was observed by various investigators. In a 17-year-old female patient the development of a congestive cardiomyopathy after acute myocarditis could be pursued for several years. After-examination of 58 patients after acute myocarditis resulted after 3 years in 62% in cardiac residual symptoms, in which cases anamnestic data and objective findings of the examination well correlated. In 14 patients (24.1%) chronic recidivating courses were found. The importance of the biopsy of the endomyocardium for the diagnostics and differential diagnostics of cardiomyopathies is represented at the instance of a 20-year-old male with subacute rheumatic myocarditis who was hospitalised on account of symptoms of a left heart insufficiency, enlargement of the heart and a picture of a left hypertrophy in the ECG. Bioptically was found a hypertrophy with formation of a large nucleus. After 1 1/2 years clinical improvement and normalisation of size of the heart and ECG. The control biopsy now resulted in normal findings of the heart.