[Morphological characteristics of hemorrhagic myocardial infarction]

The main features of hemorrhagic myocardial infarction (HMI) are presented basing on the light and electron microscopic study of 32 cases. HMI is distinguished macroscopically from the ischemic infarction by its dark-red colour due to a diffuse hemorrhagic imbibition and by the clear borders already seen within, the first hours of the disease. Histologically HMI is distinct due to the fibrinoid necrosis of the walls of small arteries, capillaries and, first of all, veins with their thrombosis. This results in the increasing vessel permeability, large hemorrhages into the interstitium with the fibrin deposits and the penetration of erythrocytes and fibrin into cardiomyocytes. Pathogenetic peculiarity of HMI is the blockade of the microcirculatory and venous bed in the background of normal coronary circulation. These events develop probably primarily in natural course of HMI and secondarily when fibrinolytic therapy is used. The thrombi of big arteries found in 9 out of 32 cases seem to arise secondarily in the background of the altered venous circulation. Possible causes of the microcirculatory-venous blockade in HMI may be persistent angiospasm, alteration of the blood coagulation, complications of the fibrinolytic therapy as well as toxicoallergic reactions and microembolism.