Ultrastructure of myocardial capillary endothelium in children with congenital heart disease.

Cardiosurgical stress initiates endothelial injury of the colliquation necrosis type (without activating coagulation necrosis) in coronary capillaries of infants aged under 1 year. The dark cells exhibited high tolerance to operation stress in the presence of labile ultrastructural response of endothelial cells of the main and light types. The percentage of dark cells does not change during surgical intervention, which is a sign predicting a favorable course of the postoperative period.