Inflammation of the myocardium that may progress to chronic dilated cardiomyopathy, most commonly due to acute viral infection (e.g., parvovirus B19, human herpesvirus 6, Epstein-Barr virus, coxsackievirus, adenovirus). Myocarditis may also develop in pts with HIV infection, hepatitis C or Lyme disease. Chagas' disease is a common cause of myocarditis in endemic areas, typically Central and South America. Noninfective causes of myocarditis include granulomatous disease (e.g., sarcoid, giant cell myocarditis), which should be considered if VT or conduction blocks dominate the presentation of heart failure in the absence of CAD.