Myocarditis is a type of heart disease. Heart disease is a general term for diseases in which the heart is diseased, caused by abnormalities in the structure and function of the heart. Heart disease includes congenital heart disease, acquired heart disease, myocarditis is a common type of acquired heart disease, which is an infectious myocardial or endocardial lesion. Myocarditis is often caused by infectious and non-infectious factors. Inflammation in myocarditis can involve the interstitium of myocardial cells, as well as the vascular components, heart valves, and pericardium, leading to damage to the structure and function of the heart. Depending on the extent of the disease, myocarditis can be categorized into focal and diffuse myocarditis. The severity of symptoms varies from no symptoms in mild cases to acute arrhythmias, heart failure, and even death in severe cases.