Myocarditis is an inflammatory disease of the heart muscle (myocardium). Most cases of myocarditis in the United States originate from a virus, and the disease may remain undiagnosed by doctors due to lack of initial symptoms. The disease may also present itself as an acute, catastrophic illness that requires immediate treatment. Although the inflammation or degeneration of the heart muscle that myocarditis causes may be fatal, this disease often goes undetected. It may also disguise itself as ischemic, valvular, or hypertensive heart disease. Myocarditis is a rare but serious condition that affects both males and females of any age.

An inflammation of the heart muscle may occur as an isolated disorder or be the dominant feature of a systemic disease (one that affects the whole body).

While there are several contributing factors that may lead to myocarditis, the primary cause is viral. Myocarditis usually results from the Coxsackie...