Wave Structure of Heart Rhythm During Tilt Test for Persons with Different Levels of Vegetative Tonus

Abstract

Introduction. It is known that there are typological features among healthy young people according to the level of autonomic tone. Accordingly, there are groups of sympatho-, normo- and vagotonics. Work has been carried out to study the influence of the initial level of autonomic tone on thereactions of the cardiovascular system in respiratory hypocapnia, pulsed ophthalmic photostimulation, in different phases of the biological cycle for women. However, there is no work on the analysis of changes in the wave structure of heart rate depending on the initial level of autonomic tone. Purpose. The aim was to determine the features of the wave structure of the heart rhythm during orthoprobe for healthy young men with different levels of tone of the autonomic nervous system at rest. Methods. Measurements were performed in conditions close to the main exchange. 117 healthy young men aged 18-23 years were examined in compliance with the requirements of bioethics. Three main spectral components were analyzed in the tRR spectrum: HF (0.15-0.4 Hz) LF (0.04-0.15Hz); VLF (0-0.04 Hz); TP (0-0.4 Hz). The amplitude of the largest peak of the tRR spectrogram in the frequency range 0.04-0.15 Hz (aLF) and its frequency (tLF) were calculated. Normalized median spectrograms of tRR oscillations were constructed.Results.A significant decrease in HF was observed in individuals of all three groups during orthoprobe. The median reactivity of reactivity was -67.3%, -77.5%, -77.9% for groups I, II and III, respectively. There were no differences between the groups due to the reactivity of this indicator. The reactivity of LF to changes in body position for sympathotonics was significantly different.The frequency of the maximum peak of the spectrogram in the range of low often resting heart rate did not differ between groups. This indicator probably decreased during orthoprobe in groups IIand III. It was found that the wave has two peaks in the vertical position in persons with different baseline levels of autonomic tone for vagotonics and normotonics in the frequency range from 0.04 to0.15 Hz. Originality. Differences in the reactivity of heart rate waves to orthoprobe for healthy young men with different baseline levels of autonomic tone were detected for the first time. Conclusions. The greatest differences in changes in the wave structure of the heart rhythm during orthoprobe for persons with different baseline levels of autonomic tone are manifested in therange of low heart rate. Spectrum reduction reactions in this range were predominant for sympathotonics. The reactions of increasing LF and the amplitude of the maximum peak of the spectrogram were predominant for normo- and parasympathotonics. It was found that the wave has two peaks in the vertical position in persons with different baseline levels of autonomic tone for vagotonics and normotonics in the frequency range from 0.04 to 0.15 Hz. Sympathotonics have one wave of orthopedic reactivity with maxima at 0.09 Hz in the low heart rate range. Normotonics have two waves of reactivity per orthoprobe with frequencies of 0.08Hz and 0.11 Hz. Parasympathotonics also have two waves with frequencies of 0.07 Hz and 0.09Hz. Prospects for further research include elucidation of the mechanisms of tRR wave formation depending on the level of vegetative tone under different conditions. Key words: wave structure of heart rhythm, vegetative tone, sympathotonics, normotonics, vagotonics.