Reference ranges of gender- and age-related heart rate variability parameters in Russian children

To obtain reference ranges for heart rate variability (HRV) parameters in healthy children, taking into account their gender and age. The study included the results of testing 22,468 children ranging 5.5-12.5 years of age. The data were grouped by age and gender. The analysis of HRV parameters was carried out according to the standards described in existing guidelines. It was based on a 5-min rhythmogram obtained from a standard 12-lead electrocardiogram (ECG). The following characteristics of the temporal and spectral analyses of HRV were studied: standard deviation of NN intervals (SDNN), power in the low-frequency band of the HRV spectrum (LF), low-frequency power as mean percentage of total power (TP) of HRV spectrum (LF%), power in the high-frequency band of the HRV spectrum (HF), high-frequency power as mean percentage of TP of HRV spectrum (HF%), power in the very-low-frequency band of HRV (VLF), and LF/HF ratio. The values of SDNN, LF, HF, HF% and TP increased with age, reaching a peak at 8 and 9 years of age. It is notable that the values of SDNN, LF and TP were significantly lower in girls in each age group. The values of LF% and LF/HF decreased with age, with a peak decrease at 8 and 9 years of age, followed by a moderate increase or stabilization. The values of LF% and LF/HF did not differ statistically significantly between boys and girls. The VLF parameter exhibited a clear trend of growth with age and had higher values in boys of each age group. The correlation between HRV and heart rate (HR) was statistically significant. The correlation graphs had similar curves in both gender groups and both age groups. The parameters of the total HRV, as well as the activity of the parasympathetic nervous system (PNS), exhibited similar growth trends with age, with a peak increase in their values at 8 and 9 years of age. HR, as well as the activity of the sympathetic nervous system (SNS), decreased with age. Gender differences also followed a consistent pattern: parameters characterizing the activity of the peripheral nervous system were significantly higher in boys than in girls across all age groups.

Acute effects of exercise on cardiac autonomic function and arterial stiffness in patients with stable coronary artery disease

Objectives. To examine the acute effect of a maximal aerobic exercise effort on aortic, peripheral arterial stiffness and cardiovagal modulation of trained and untrained patients with coronary artery disease (CAD). Design. Cross-sectional study. Methods. Eighteen untrained patients with CAD, 18 trained patients with CAD, and 18 apparently healthy trained subjects were sampled and matched for age and body mass index. Aortic and peripheral stiffness were measured by applanation tonometry estimates of carotid-femoral (cfPWV), carotid-radial (crPWV), and carotid-dorsalis pedis pulse wave velocity (cdPWV), respectively. Cardiovagal modulation was assessed by heart-rate variability (HRV) indices including the standard deviation of normal-to-normal RR intervals (SDNN), root-mean-square of successive differences (RMSSD), and the high-frequency power band (HF). cfPWV, crPWV, cdPWV, and HRV indices were measured at rest, 10 and 30 min following a maximal cardiopulmonary exercise test on a cycle ergometer. Results. No differences were observed between groups at rest nor over time in indices of HRV, cfPWV and cdPWV. Still, main effects of time were observed in cfPWV (p < .001; ɳ² = 0.313) and cdPWV (p = .003, ɳ² = 0.111), RMSSD (p < .001, ɳ² = 0.352), HF (p < .001, ɳ² = 0.265) and LF/HF (p = .001, ɳ² = 0.239), as cdPWV, RMSSD, and HF were reduced 10 min following exercise, whereas cfPWV and LF/HF were increased. Changes in cPP were associated with changes in HRV from rest to min 10 (HF, r = 0.302), and to min 30 (HF, r = 0.377; SDNN, r = 0.357; RMSSD, r = 0.429). Conclusion. Training level and CAD do not seem to influence arterial stiffness and cardiac autonomic responses to maximal exercise.

Gender-related specificities of photoplethysmogram spectral assessment dynamics in healthy subjects during the passive tilt test

The goal of our study was to investigate gender-related specificities of photoplethysmogram (PPG) spectral assessment dynamics in healthy individuals during the passive tilt test. Material and Methods — The study involved 38 men (33±7 years old) and 15 women (27±8 years old). The PPG signal was recorded for 10 minutes in the horizontal and vertical positions of the human body (passive tilt test). The following spectral parameters of PPG were calculated: HF%, LF%, and LF/HF. Results — In the horizontal body position, men had significantly higher values of the LF% index. In the course of the passive tilt test, an increase in HF% was observed by almost 1.5 times in men and by more than 5 times in women. Significant differences in the values of vegetative indicators were achieved: in women, HF% values exceeded those in men, while LF% values were noticeably lower. Conclusion — Men displayed signs (assessed by LF%) of augmented sympathetic activity, relative to women, at all stages of their passive tilt test. During the transition from the horizontal to the vertical position, a significant increase in respiratory influences (assessed by HF%) on PPG signal components was established, which was more pronounced in women.

Capabilities of photoplethysmography as a method for screening of cardiovascular system pathology

Currently, vegetative dysfunction considered to be one of principal mechanisms in the pathogenesis of cardiovascular pathology, which causes a cascade of events leading to changes in the properties and a structure of vascular wall. This review article contains literature from various databases (Russian science citation index, PubMed, Google Shcolar, Scopus). It presents the methods for assessing vegetative imbalance. In particular, the method of photoplethysmography (PPGV) is considered for recording periodic fluctuations at various frequencies in the distal vascular bed which characterize physiological processes (cardiac activity, respiratory influences, neurogenic, myogenic and endothelial activity). In addition, other diagnostic capabilities of PPGV such as heart rate (HR) assessment, determining the properties of vascular wall and the level of blood saturation are elucidated. This paper demonstrates a wide range of PPGV applications. The simplicity of PPGV reproduction and its cost-effectiveness make it feasible both in routine clinical practice for the purposes of screening for cardiovascular pathology, and for individual health monitoring incorporated in smart devices.