Right heart ventricle myocarditis induced by pulmonary thrombembolism

Deep venous thrombosis and pulmonary thrombembolism are referred to as venous thrombembolism. Pulmonary thrombembolism affects the right ventricle. Two morphologically and clinically distinct conditions are distinguished according to change of blood pressure and speed of blood pressure increase in the pulmonary artery - acute and chronic cor pulmonale. Acute cor pulmonale develops during rapid increase (within seconds) of blood pressure in the pulmonary artery. Morphologically, the condition leads to dilatation of the right ventricle and clinically to sudden cardiac death or severe circulatory instability. Chronic cor pulmonale represents myocardial hypertrophy of the right ventricle as a response to the gradually increasing pressure in the pulmonary artery. Herein, we demonstrate a rare case report of right ventricular myocarditis in a 51-year-old woman with pulmonary thromboembolism and morphological signs of chronic pulmonary hypertension. This non-infectious myocarditis is histologically characterized by myocardial damage (myocytolysis) and dominant histiocytic and neutrophil infiltration accompanied by scanty T-lymphocytes. These inflammatory changes differ from those associated with myocardial infarction. The possible pathological mechanisms of right ventricular myocarditis induced by pulmonary thrombembolism are discussed.