Features of frequency domain indicators of HRV at elderly patients with arterial hypertension

Was studying of features of the central hemodynamics and a vegetative regulation of variability of a cordial rhythm depending on age. Research included 65 patients with AH of the 1st and 2nd degree (the main group: 35 men and 30 women), at the age of 20–65 years who are constantly living in Tashkent. With evaluation of age all indicators of HRV were significantly decreased.

Keywords:arterial hypertension, heart rate variability

Изучение особенностей центральной гемодинамики и вегетативной регуляции вариабельности сердечного ритма в зависимости от возраста. Были обследованы 65 пациентов (основная группа 35 мужчин и 30 женщин), в возрасте от 20 до старше 65 лет с АГ 1 и 2 степени (ВОЗ/МОАГ (1999 г)), постоянно проживающих в городе Ташкенте. Было установлено, что с возрастом отмечается снижение всех параметров ВСР.

Ключевые слова: артериальная гипертензия, вариабельность сердечного ритма

AH is considered today as a polyetiological disease at which any of the existing theories of a pathogenesis completely doesn't explain all reasons of rising of the ABP. The extremity of the 20th century was marked not only intensive development of fundamental ideas of the arterial hypertension (AH), but also critical revision of a series of regulations on the reasons, mechanisms of development and treatment of this disease. Research of a condition of a vegetative nervous system and its functionality became one of the perspective and still insufficiently developed directions of studying of a pathogenesis of an idiopathic hypertension.

In recent years in medicine the close attention is paid to studying of a functional condition of vegetative system on the basis of a method of the analysis of variability of a cordial rhythm. As the vegetative nervous system carries out integrative function on ensuring processes of adaptation, studying of time and spectral indicators of HRV allows to estimate a condition of vegetative providing, the general activity of regulatory mechanisms, activity of segmentar and the supragmentar structures. Functionality of the blood circulatory system goes down with age therefore process of adaptation of cardiovascular system at persons with the increased arterial pressure is particular important.

Purpose: was studying of features of the central hemodynamics and a vegetative regulation of variability of a cordial rhythm depending on age.

The diagnosis of AH I-II of degree was established on the basis of classification of an arterial hypertension of WHO/ISH, 1999 and Russian society of Cardiologists, 2004. At diagnostics of AH of the I degree were guided by the following signs of DAD at rest from 90 to 99 mm hg and systolic arterial pressure — 140–159 mm hg, within a day it changed. AH II of degree was diagnosed at the level of diastolic arterial pressure at rest ranging from 100 to 109 mm hg and systolic arterial pressure — from 160 to 179 mm hg.

All examined patients of the main group depending on age were sectioned into 3 subgroups (A,B,C). Subgroup A persons of young age of 25–44 years. The subgroup B middle-aged persons from 44 to 55 years. The subgroup C elderly people of 60 years and over. AH duration at patients of the A subgroup was 2,05±0,75 years, patients of B subgroup 4,71±2,6 years, in the C subgroup 6,71±3,6 years.

During scientific research of 65 patients with AH I-II of degree were surveyed by modern, high-informative methods of research. The diagnosis of patients was established according to clinical and laboratory and instrumental methods of research.

Criteria of including in research were patients with AH I-II of degree and obligatory registration of a sinus rate for an ECG.

Results: In the analysis of frequency indicators of HRV it is noticed that with age at patients with AH depression of absolute power of VLF, LF and HF components, and as a result of it, the general power of a range of TP (2493,7±69,2 ms2 — in A subgroup, 999,1±54,69 ms2 in B subgroup (р<0,01) and 807,6±78,3 ms2 — in C subgroup takes place (р<0,001)).

Table 1

Average values of frequency domain parameters of HRV at patients with AH taking account their age (M±m)

Between surveyed B and C subgroups, revealed difference concerned LF ratio (346,3±79,3 and 202,4±59,51; р<0,001) and HF (377,8±25,27 and 265,8±22,41; р<0,05), and also thereof a reliable difference of ratios of LF/HF for 47 % (р<0,01).

Differences on all indicators of the low-frequency and high-pitched making HRV expressed in the normalized units were observed between A and B subgroups of examined. At the same time, in the C subgroup in comparison with B subgroup only Lfn_d, Lfn_n and Hfn_n values were authentically reduced. Changes of other indicators of the low-frequency and high-pitched making HRV expressed in the normalized units between surveyed B and C subgroup, had character of a tendency.

Table 2

Thus, at patients with arterial hypertension gradual depression of HRV connected with age. Considering that on this background the average CCR isn't enlarged and decreases. This age dynamics reflects process of gradual depression of vegetative influences on a cordial rhythm, but not intensifying of sympathetic influences. With age the depression of the general power of a range of HRV due to the prevailing depression low of LF and insignificant depression of high-pitched HF of a component is bound. As depression of LF and HF happens not synchronously, LF/HF relation significantly decreases. Further parameters of variability of a rhythm of heart between healthy persons and patients with arterial hypertension in age aspects were analyzed. Results of this research are presented in table 1,2.

Table 3

Comparative characteristic of HRV at patients with AH of elderly age (М±m)

At the same time depression and sympathetic and parasympathetic influences becomes perceptible. However decrease of activity of a sympathetic nervous system at patients with AH of elderly age which was more expressed is confirmed by results of the analysis of balance between sympathetic and parasympathetic system.

Conclusion: Analyzing data of HRV in subgroup (C) of elderly age it is established that on a series depression of all HRV parameters, the relative augmentation of parasympathetic influences of SNS becomes perceptible. What is confirmed by minor changes of time indicators of RMSSD and pNN5 characterizing a parasympathetic nervous system. These changes were confirmed also from a frequency analysis of HRV. In particular at patients with AH of elderly age insignificant depression of HF on the relation with LF becomes perceptible. At the same time fluctuation of a share of HF in a range of a cordial rhythm and decrease of the relation of LF/HF, in comparison with other age groups, indicates shift of balance towards activation of parasympathetic department.