Diagnosis of myocarditis has improved with the application of new techniques such as immunohistochemistry, polymerase chain reaction, in situ hybridization and Southern blot in endomyocardial biopsies. Treatment of inflammatory heart disease is still difficult and not yet validated by a study with patient numbers sufficient to allow statistical analysis. The European Study of Epidemiology and Treatment of Cardiac Inflammatory Disease (ESETCID) addresses problems of aetiology, pathogenesis and specific treatment of myocarditis. It is the first multicentre, double-blind placebo-controlled randomized study, apart from the Myocarditis Treatment Trial, to discriminate between different forms of myocarditis. Patients with cytomegalovirus-induced myocarditis are treated by hyperimmunoglobulin compared to placebo. Patients with enterovirus-positive myocarditis will receive interferon alpha vs placebo. Patients with virus-negative myocarditis, which is considered autoimmune, will be treated with immunosuppression compared to placebo. The primary endpoint of this study is an improvement in ejection fraction of more than 5%. This trial may give a better understanding of the course of myocarditis, leading to more specific treatment which may in turn reduce the number of patients with post-myocardial heart muscle disease who require heart transplantation as a final therapeutic remedy.