Myocarditis can have many diverse presentations ranging from ventricular arrhythmias to congestive heart failure, secondary to dilated cardiomyopathy. The recent resurgence of endomyocardial biopsy has greatly enhanced our ability to diagnose this intriguing entity. The biopsy has shown that unexplained arrhythmias have a 15% to 29% incidence of myocarditis, while those with an idiopathic congestive cardiomyopathy have a biopsy-proved range of 9% to 63%. The cause of this process has, at times, been blamed on viruses, but definite cause-and-effect relationships are mostly conjecture and anecdotal. The current role of immunosuppressive therapy in myocarditis is potentially promising, and may alter the subsequent course of the illness.