[The role of changes in the bioelectrical activity of the cardiomyocytes in the antiarrhythmic effect of adaptation to hypobaric hypoxia].

The adaptation to periodic hypoxia increases the AP duration in the cardiomyocytes of the rat isolated cardiac papillary muscles; prevents the depression of the resting potential, of the AP amplitude and duration in high calcium concentration and high-frequency stimulation. The adaptation also limits the contracture of papillary muscles and the depression of the resting potential in the cardiomyocytes in hypo-sodium solution. The adaptation seems to enhance the efficacy of the membrane mechanisms of the ion transport in cardiomyocytes, whereas subsequent changes in bioelectrical activity play a major part in antiarrhythmic effect of the adaptation.