Introduction. Scar tissue is much harder than muscle fibers, and it is not involved in the process of active contraction of the myocardium, which reduces the functionality of the latter. Focal post-infarction myocardial fibrosis expands over time, which is accompanied by decrease of its contractility and progression of heart failure. The mechanisms of this phenomenon remain poorly understood. Purpose. To study the mechanism of progression of the post-infarction scar. Materials and methods. 34 sectional preparations of the hearts of patients, who died because of various reasons at different times after myocardial infarction (from 48 h to 12 years), were histologically examined. Results and discussion. A microscopic examination of the peripheral part of the basin of the occluded artery in the area of myocardial infarction (MI) shows pronounced edema of the connective tissue due to the increased permeability of damaged microvessels, which leads to hypoxia of cardiomyocytes (CMC) on the background of decrease of the number of perfused capillaries. Some of them undergo apoptosis, others are in the state of hibernation, from which the cell can go into the stage of self-destruction or can restore its morphofunctional properties. The formed scar exerts increased resistance to the functioning CMC from the arterial pools associated with the infarction zone, as a result of which the CMC undergo compensatory hypertrophy. When CMC hypertrophy enters the decompensation phase, the cell is destroyed and replaced by fibrosis. From this, it follows that in the long-term MI, any factors that lead to increased load on CMC (arterial hypertension, etc.) can accelerate the decompensation of CMC hypertrophy with the spread of postinfarction fibrosis. Сonclusions. In acute MI in the zone of complete arrest of blood flow in microvessels, necrosis of all myocardial structures develops and ends with the formation of a compact scar. On the periphery of the infarction in the areas of the supplied blood supply, due to decrease of the total num [...]
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