Viral myocarditis is a rare cardiac disease associated with the inflammation and injury of the myocardium. The downstream effects are a product of cooperation between viral processes and both the adaptive as innate host's immune response. Acute appearance of myocarditis is mostly idiopathic, i.e. of unknown origin. Primarily established on clinical observation and limited epidemiologic studies. Most studied cases are coxsackie, adeno and human immunodeficiency virus. Grey compartments describe extracellular matrix. Direct lines indicate downstream effects and dashed lines indicate speculative research.