Criteria for predicting bioelectrical processes in the human heart under various stages of acute hypoxia

Despite much available information on the heart activity under acute normobaric hypoxia (ANH), there are no data on the leading ECG components and the criteria for predicting their deviations at various stages of ANH and depending on its duration. The aim of the paper is to determine the leading ECG components and the dependence of their deviations on the initial parameters at different stages of acute normobaric hypoxia and depending on its duration in a healthy person. Materials and Methods. The shifts in parameter indicators were determined in two groups of men (aged 18-26) under 20-minute mild (14.5 % O2, nt=30) and medium (12.3 % O2, n2=29) ANH. During the study the authors used 7 ECG parameters and oximetry. Statistica 10.0 software package was used for data processing. The authors determined normality of distribution, they also used factor analysis, correlation, and regression. Results. For all ANH degrees, the leading factor included QT, TJI, and (with one exception) RR. In case of mild ANH, the 1st factor was supplemented by PiII at the 5th minute of exposure, and in case of medium ANH at the 20th minute. The second most important factor in case of mild ANH was determined by BAr and RII at the 5th and 20th min and by BAR at the 10th min. In case of medium ANH it was supplemented by PjII at the 5th min, by RII and BAR at the 10th min, and by BAL at the 20th min. It was shown that in case of mild ANH PJI, RII, BAr, and RR deviations reliably depend on the initial parameters; for medium ANH, such dependence is observed for RR and QT at the 5th and 10th min, for RII at the 10th and 20th min, and for PJI at the 20th min. Conclusion. The main markers of heart bioelectrical processes under ANH are QT, TJI and RR, other parameters are variable. The availability to predict deviations of ECG parameters by their initial parameters depends on ANH stage.