The incidence of congestive heart failure (CHF) is increasing dramatically and CHF is now the most common diagnosis-related group for patients over 65 years of age admitted to hospital. Determining the etiology of heart failure is critical, as this defines the patient’s natural history and treatment options. Despite a full evaluation of patients with new-onset or progressive heart failure utilizing traditional techniques, including endomyocardial biopsy (EMB), approximately 50% of patients are deemed “idiopathic” in origin. A “virus” is suspected as the cause of most cases of nonischemic cardiomyopathy and, if true, viral myocarditis diagnosis and treatment represent a remarkable opportunity to alter the observed increase in cardiac dysfunction and heart failure. In this issue of Dialogues in Cardiovascular Medicine, the world’s experts in myocarditis address our current understanding of the pathophysiology and treatment of this disorder.

Dr Cooper addresses nonviral causes of myocarditis, including giant cell myocarditis, sarcoidosis, and hypersensitivity eosinophilic myocarditis. While the etiology of each of these nonviral disorders is unclear, the pathophysiology, as currently defined (immune, inflammatory, and allergic), does allow appropriate management. Each of these disorders is relatively rare and accounts for only a small portion of those patients in the idiopathic cardiomyopathy category...