[Characteristics of glucose and lactate oxidation in the myocardium at different stages of mitral stenosis].

Content of glucose, lactate, pyruvate and cAMP was estimated in biopsy from left atrium of 120 patients with the III and IV degree of mitral valve stenosis. Content of 14CO2, developed after incubation of myocardium homogenates with labelled substrates--glucose, glucose-I-phosphate, glucose-6-phosphate, succinate, lactate, was also measured. In patients with the IV degree of mitral valve stenosis concentration of carbohydrates and cAMP was decreased in myocardium as compared with those of patients with the III degree of the disease, whereas consumption of labelled glucose, lactate and succinate was increased. Estimation of the oxidation rate of glucose phosphorylated derivatives enabled to suggest that main part of glucose carbon was involved in reactions of the Krebs cycle. At the same time, a decrease in the content of carbohydrate substrates in myocardium of patients with the IV degree of the stenosis occurred due to elevated rate of these substrates oxidation. The data obtained suggest that adaptation reactions to hemodynamic impairments were responsible for dissimilar character of glucose and lactate metabolism in myocardium of patients with various degree of mitral valve stenosis.