Myocarditis is an inflammation of the heart muscle.

Myocarditis is collection of diseases of infectious, toxic, and autoimmune. Myocarditis may develop as a complication of an infectious disease, usually caused by a virus. It can occur in people of all ages and is diagnosed more often in men than in women. Myocarditis is likely caused by a wide variety of infectious organisms, autoimmune disorders, and exogenous agents, with genetic and environmental predisposition. Myocarditis is defined as inflammatory changes in the heart muscle and is characterized by myocyte necrosis. Many organisms can infect and injure the heart. Type B, a virus among those that usually infect the gastrointestinal tract, is believed to be the most common offending agent. Many other viruses, such as those of polio, rubella and influenza, have been associated with myocarditis. Myocarditis can occur as a rare complication of bacterial infections, including diphtheria, tuberculosis, typhoid fever, and tetanus. Other infectious organisms, such as rickettsia and parasites, may also cause inflammation in the heart muscle.