[Features of myocardial metabolism of adenylic nucleotides in patients with paroxysmal tachycardias].

The authors revealed that concentrations of inosin, hypoxanthine and their total levels in the arterial blood and the blood of the coronary sinus in patients with paroxysmal tachycardias are higher than the corresponding levels in patients with chronic forms of coronary heart disease and neurocirculatory dystonia. In the absence of tachycardia, there was an accelerated metabolism of adenyl nucleotides of the myocardium: the myocardium produced inosin and extracted hypoxanthine. It is suggested that this type of metabolism of adenyl nucleotides requires additional energy expenditures as compared with the energy supply of the nucleotide metabolism of the healthy myocardium and may be one of the reasons underlying the development of tachycardiac paroxysm, with the place of the localization of the re-entry and/or the presence of coronary heart disease having no significant effect on the metabolism of adenyl nucleotides of the myocardium in such patients. The emergence of tachycardia leads to a decreased extraction of hypoxanthine by the myocardium as compared to the baseline and to insignificant elevation in the production of inosin which causes an increase in the levels of these metabolites in the arterial blood and the blood of the coronary sinus.