Early clinical profiles of cases with histopathologically proven acute idiopathic myocarditis and a proposal for diagnostic criteria.

The early clinical features, primary care, treatment and short-term prognosis in 15 cases of acute myocarditis where diagnostic confirmation was made by endomyocardial biopsy or autopsy were analyzed. Characteristically, idiopathic myocarditis of possible viral etiology revealed preceding symptoms which consisted of flu-like symptoms, i.e., fever, upper respiratory infection (sore throat, cough), myalgia or arthralgia, general malaise, and gastrointestinal disorders (vomiting, anorexia, nausea, abdominal pain and soft stool). A severe cardiac or generalized disease condition may follow. Depending upon the progress of intensive medical and cardiac care, the patients' prognosis is not always poor. Diagnostic criteria based upon our own experience have been constructed as a proposal.