[Ultrastructure of the microcirculatory bed of the myocardium in coronary insufficiency].

The features of microcirculation in the myocardium were studied experimentally in 20 dogs when the blood flow in the skirting branch of the left coronary artery was limited by 30 and 50%. The disorders developing in the zone of ischemia were found to consist of a number of adaptative and pathological changes: changes in the tension of microvessels with predominant dilatation of the venous genu; occlusion of the capillary lumens with extremely swollen endothelial cells and sometimes their compression by edematous cardiomyocytes; aggregations of red blood cells; dilatation of interendothelial junctions: activation of micropinocytosis; intestitial edema. The experimental results indicate that disorders in microhemocirculation, transport and intermediary metabolism are one of the causes of contractile myocardium damage when a focus of ischemia develops in it, alongside with the limitation of the flow capacity of the main artery.