Myocarditis is a heart disease that usually has a viral etiology. Giant cell myocarditis is a form of chronic interstitial myocarditis characterized by inflammatory damage to the myocardium and severe hypertrophy of cardiomyocytes. Myocardial damage is caused by the proliferation of antigen-dependent T lymphocytes with giant cells due to prolonged reactivation of the SVCT-2 virus (human T-cell leukemoid virus. Clinical manifestations of giant cell myocardial process may include constitutional manifestations (asthenia, lethargy, fatigue, muscle pain, headache, fever, hypotension), heart rhythm disturbances (tachycardia, arrhythmia, prolongation of the QT interval, right bundle branch block, atrial fibrillation).Treatment of the giant cell form of myocarditis should be systemic and monitored by a cardiologist and an infectious disease specialist.