**6. Conclusions**

It is not easy to explain myocarditis concisely and clearly because there are varieties of causes, clinical types, clinical courses, and the severity of circulatory failure. Some patients present with common cold-like symptoms, whereas others require mechanical circulatory support in the ER because of a suddenly developing circulatory crisis. Information of the patient's background and clinical history is essential when deciding on a treatment plan for myocarditis in most cases, although we are sometimes unexpectedly confronted with emergency conditions regarding these patients in the ER.

Currently, the most troublesome issue in the course of treating myocarditis is when to perform a myocardial biopsy for a definitive diagnosis. Although noninvasive diagnostic methods such as CMR have been developed to reduce the risk of serious complications and physical strain on the patient, an effective diagnosis cannot be established during the acute phase. Regarding the treatment for myocarditis, we cannot presently exclude original causes in many cases and can only provide unpredictable "bridge" support, such as PCPS or VAS.

Many patients with myocarditis can survive if we remember the possibility of myocarditis in the differential diagnosis and provide immediate, adequate treatment. When we face illness of unknown origin in patients with a severe arrhythmia or circulatory failure, we should immediately assemble the medical staff and prepare cardiac support. Any delay in treatment can allow abrupt deterioration of the circulation. Additionally, we should establish a system of simultaneous processing of the histological diagnosis to decide on the propriety of immunoregulation therapy.
