N. K. Chemeris

Changes in the cardiovascular system are systemic during aging. The aim of this work is to describe systemic patterns of changes in heart rate variability (HRV) parameters during aging in healthy subjects. HRV data of 73 healthy subjects aged 11–76 years from the PhysioNet database were used, which were divided into three groups: young (11–17 years old), middle-aged (24–55 years old), and elderly (56–76 years old). Using the Hilbert–Huang method and wavelet analysis, spectral curves of empirical HRV modes were obtained, for which the maxima and their corresponding frequencies were determined. Nine modes were identified. A twofold decrease in the autonomic control modes and, to a lesser extent, in the very-low-frequency modes (0.002–0.04 Hz) was found in the elderly compared to the young. Very-low-frequency HRV oscillations (<0.001 Hz) did not change with age. The results obtained may serve as a basis for physiological interpretation of HRV regulation processes and may be useful in the development of controlled anti-aging therapy.

The aim of the study was to reveal the patterns of the age-related dynamics of the frequency-dependent regulation of heart rate variability (HRV) based on the analysis of Holter ECG recordings from healthy subjects of four age groups: neonates, one-year-old infants, adolescents, and adults. A wide spectral composition of HRV is shown, consisting of nine Hilbert–Huang modes in the frequency range from 0.0001 to 2 Hz. A decrease in the central frequencies of all modes is shown in the postnatal period with a plateau in adolescence. A rapid progression of systemic humoral regulation of HRV, characterized by a consolidated increase in the amplitudes of the corresponding modes with a plateau in adolescence, is demonstrated. The dome-shaped character of age-related changes in amplitude of modes associated with autonomic control with a maximum in adolescence is shown. The results obtained quantitatively demonstrate age-related consolidated changes in HRV parameters from neonates to adulthood.

The dynamics of the pulse wave (PW) associated with the PW transit time variability (PWTTV) determines the peripheral pulse rate variability, which is used as a surrogate for heart rate variability (HRV). The aim of the work is to analyze the frequency-dependent dynamics of PWTTV and to identify the possible frequency-phase modulation of PW velocity oscillations on the transit from the heart to the soft tissues of the distal parts of the upper extremities. RR-interval recordings and synchronous records of photoplethysmograms of 12 conditionally healthy subjects from the PhysioNet open database were used in this work. Using the Hilbert–Huang transform 3 spectral components of PWTTV and HRV were identified. It was shown that the amplitudes of PWTTV oscillations were many times (up to 8.4 times) smaller than the amplitudes of HRV, and the peaks of PWTTV spectral components were shifted towards higher frequencies than those of HRV. Functional relations between PWTTV and HRV, which can determine the phase modulation of periodic changes in the velocity of propagation of PW, were revealed.

The dynamics of the pulse wave (PW) associated with the PW transit time variability (PWTTV) determines the peripheral pulse rate variability, which is used as a surrogate for heart rate variability (HRV). The aim of the work is to analyze the frequency-dependent dynamics of PWTTV and to identify the possible frequency-phase modulation of PW velocity oscillations on the transit from the heart to the soft tissues of the distal parts of the upper extremities. RR-interval recordings and synchronous records of photoplethysmograms of 12 conditionally healthy subjects from the PhysioNet open database were used in this work. Using the Hilbert–Huang transform 3 spectral components of PWTTV and HRV were identified. It was shown that the amplitudes of PWTTV oscillations were many times (up to 8.4 times) smaller than the amplitudes of HRV, and the peaks of PWTTV spectral components were shifted towards higher frequencies than those of HRV. Functional relations between PWTTV and HRV, which can determine the phase modulation of periodic changes in the PW propagation velocity, were revealed.

Analysis of heart rate variability (HRV) is widely used for noninvasive assessment of the state of the regulation systems of the heart. The aim of this study was to evaluate the capabilities of the Hilbert–Huang method for calculating spectral parameters of HRV in comparison with the commonly used Fourier analysis. Fourier analysis allows estimation of averaged spectral amplitudes and power of HRV oscillations in fixed frequency intervals, which are associated with the activity of sympathetic, parasympathetic, and humoral regulation systems. Using the Hilbert–Huang method, we revealed four spectral components, described by Gaussian functions, in which HRV oscillations are concentrated, and showed the absence of fixed boundaries between them. The obtained energy quantitative characteristics of the spectral components of heart rhythm oscillations can serve as the basis for diagnostic methods of heart rhythm regulation, supplementing the commonly used ones.

Analysis of heart rate variability (HRV) is widely used for noninvasive assessment of the state of its regulation systems. The aim of the research was to evaluate the capabilities of the Hilbert-Huang method for calculating spectral parameters of HRV in comparison with the commonly used Fourier analysis. Fourier analysis allows to estimate averaged spectral amplitudes and power of HRV oscillations in fixed frequency intervals, which are associated with the activity of sympathetic, parasympathetic and humoral regulation systems. Using the Hilbert-Huang method, we revealed 4 spectral components, described by Gauss functions, in which HRV oscillations are concentrated, and showed the absence of fixed boundaries between them. The obtained energy quantitative characteristics of the spectral components of heart rhythm oscillations can serve as the basis for diagnostic methods of its regulation, supplementing the commonly used ones.