Myocarditis is a group of inflammatory imunoprocesses related to myocardium with clinical and histopatological manifestations. There are several types of myocarditis such as fluminative, acute chronic and chronic persistent myocarditis as well as GCM (giant cell myocarditis). Myocarditis is most often caused by viral infection in as many as 40% of all cases of myocarditis, other causes are bacterial, fungal and parasitic infections, furthermore it can be caused by hypersensitivity to medications, cardiac manifestations of sarcoidosis, lupus etc. Myocarditis affects 22 in 100000 people and its prevalence between 1990. and 2013. remains stable. The mortality of myocarditis has seen decline in 2005. Diagnosing the disease has been improved by high-sensitivity magnetic resonance imaging, through which sarcoidosis can also be diagnosed. For diagnosing, echocardiography can also be used, which shows the enlargement of the heart cavities and endomyocardial biopsy, whose percision can be increased with the use of an electrogram, which proves inflammatory infiltrates. The most common symptoms of the disease are increased body temperature (fever), weakness, flatulence, tachycardia and other signs of heart failure. Myocarditis can also cause occurance of dilated cardiomyopathy.