Ventricular Repolarization of the Heart of Cross-country Skiers at Different Stages of the Annual Training Cycle

Abstract

The study of the heart electrical activity of cross-country skiers with a high sports qualification has been carried out at different stages of the annual training cycle. It has been found that the morphofunctional cardiac reconstructions associated with an increase in the intensity of physical workloads from the preparatory cycle to the competition stage lead to a change in the repolarization of the ventricles: the early repolarization duration of the ventricles (the Tpeak-Tend_II interval) was significantly decreased during the recovery from submaximal exercise on ECG_II; the negative extremum amplitude of the cardio electric field on the body surface of athletes increases significantly with an insignificant increase in the amplitude of the T wave on the ECG_II. The individual cardioelectrotopographic analysis of the cardio electric field on the body surface of the examined athletes during the period of ventricular repolarization showed a change in the amplitude–time dynamics of the extrema at the competition stage in comparison with the preparatory stage.