Heart Electrical Activity during Ventricular Repolarization in Subjects with Different Resistances to Hypoxia

Abstract

The study of the electrical activity of the heart during ventricular repolarization period of healthy subjects with different resistances to oxygen deficiency to exposure of normobaric hypoxic hypoxia (12.3% O₂) has been carried out using the simultaneous recording of the heart electrical unipolar potentials from a variety of leads on the body surface. It was revealed that in subjects with different resistances to a hypoxic stimulus the correlation of change in QT, J-TpeakII and Tpeak-TendII intervals under the influence of acute hypoxia was different: in subjects with a high resistance to hypoxia the decrease in the QT interval corresponded to the decrease in ventricular late repolarization duration, and in subjects with low resistance to hypoxia the decrease in the QT interval corresponded to the periods of early and late repolarization. The analysis of the cardioelectric field on the body surface of subjects with different resistances to a hypoxic stimulus revealed a statistically significant decrease in temporal characteristics of maximum cardioelectric potentials while amplitude characteristics remained practically unchanged independently of resistance to hypoxia.