Development of standards of indicators of HRV received in the analysis of long records ECG at almost healthy persons taking into account the age. For realization of a goal 33 almost healthy persons were examined (group of comparison: 18 men and 15 women) at the age of 20–65 years.
Keywords: arterial hypertension, heart rate variability
Разработка стандартов ВСР полученных при использовании длительных записей ЭКГ у практически здоровых лиц. Были исследованы 33 здоровых добровольца (18 мужчин и 15 женщин) в возрасте от 20 до старше 65 лет.
Ключевые слова: артериальная гипертензия, вариабельность ритма сердца
One of the methods allowing estimate balance sympathetic and parasympathetic nervous systems is determination of variability of a cordial rhythm. The proved communication between predisposition to fatal arrhythmias and signs of a vagosympathetic imbalance stimulated development of quantitative indices of vegetative activity and calculation of their standards. At an assessment of variability of a rhythm of heart broad development was gained by methods of time and spectral analysis of an ECG.
Due to the larger range of fluctuations of values of indicators of HRV, there is a question of development of standards. In literature the sizes of these indicators at healthy persons received in the analysis of short records while reports on values of the HRV parameters in the analysis of long records ECG are meet single.
Purpose: Development of standards of indicators of HRV received in the analysis of long records ECG at almost healthy persons taking into account the age.
Materials and methods: For realization of a goal 33 almost healthy persons were examined (group of comparison: 18 men and 15 women) at the age of 20–65 years. Work was carried out on the basis of the republican specialized scientific and practical medical center of therapy and medical rehabilitation during 2013–2014.
All examined patients of control group depending on age were sectioned into 3 subgroups (A, B, C). Subgroup A persons of young age of 22–44 years. The subgroup B middle-aged persons from 44 to 55 years. The subgroup C by elderly people of over 60 years. Average age of persons of I group (CG) in A subgroup was 27,9±6,34 years, in B subgroup 48,47±6,55 years and 65,73±6,32 years in C subgroup.
Research of a condition of HRV was carried out by means of Holter monitoring of a daily ECG. For registration and the analysis of an ECG used installation of the Cardio Sens system (the HAI-medik, Kharkiv) and the software of the same firm. For an assessment of HRV indicators of a time and frequency analysis were used. For an exception of pathology of cardiovascular system the standard electrocardiography, an echocardiography, were carried out. In the analysis of results of ECG monitoring the listed above indicators of HRV paid separately for the day and night periods, and also per day in general.
It is considered that HRV indicators received in the analysis of short records strongly depend on various external influences, such as psycho-emotional loads, a physical strain, change position of a body, etc., in communication with what processing of results of 24-hour monitoring allows to receive stable results reproduced at repeated researches.
Indicators of HRV change depending on age of patients that needs also to be considered at development of standards. Statistical analysis of the functional and morphological changes in an organism carried out on three age the period — till 25–44 years (A subgroup), of 44–60 years (B subgroup), over 60 years (B subgroup). Results of the analysis are presented in table 1 and 2.
Table 1
Average values of time domain indicators of HRV at healthy people taking into account their age (M±m)
|
Indicator |
Age category (n=33) |
||
|
(А)25–44 years (n=12) |
(В) 44–60 years (n=11) |
(С) over 60 years (n=10) |
|
|
mRR, mc |
855,4±15,1 |
800,5±16,8** |
755,7±17,0***• |
|
SDNN, мс |
176,2±6,01 |
151,8±6,09* |
144,9±6,12** |
|
SDANN, мс |
2770,1 ±217,9 |
2237,2±235,7** |
1762,3±225,3*** • |
|
SDNNi, мс |
2176,7±210,4 |
1463,9±243,3** |
1109,5±217,6*** |
|
RMSSD, мс |
43,9±4,36 |
25,4±3,01** |
23,0±3,16** |
|
pNN50, % |
22,0±3,60 |
15,8±3,47* |
9,9±4,28** • |
|
Note: * р <0,05; **р < 0,01; ***р < 0,001 in relation to subgroup A; • р <0,05; ••р < 0,01 Values between A and C subgroups. |
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Apparently from the submitted data that on all temporary indicators of HRV between examined «A« and «B« age groups statistically significant differences are taped.
In particular, it was established that with augmentation of age depression of the HRV time parameters become perceptible. In subgroup of middle-aged persons statistically significant depression of indicators of mRR for 10,2 %, by SDNN for 16,6 % and SDNNi for 48,2 % which characterize the general cooperative activity of VNS is taped (p<0,05). Along with depression of the general power of HRV there is a reliable depression of an indicator of SDANN for 49,5 % became perceptible (p<0,05) specifying depression of sympathetic influences in subgroup of middle-aged persons.
In the analysis of the HRV time parameters characterizing parasympathetic influence of VNS their reliable depression of RMSSD (ms) for 70,1 % and pNN50 for 37,5 % is also taped (p<0,01).
Though comparison of indicators of HRV «A« and «C« subgroups is represented to us not quite correct because of an appreciable age difference, the comparative analysis of the HRV parameters between subgroups young (A) and elderly (C) revealed significant decrease of all time indicators of HRV (p<0,01).
Table 2
Average values of time domain indicators of HRV at healthy people during the day time (M±m)
|
Indicator |
(А)25–44 y (n=12) |
(В) 44–60 y (n=11) |
(С) over 60 y (n=10) |
|
RMSSd, мс |
37,0±3,93 |
20,3±4,12** |
19,6±4,14*** |
|
RMSSn, мс |
58,50±5,25 |
36,0±5,3** |
29,5±5,7***•• |
|
pNN50d, мс |
15,9±2,9 |
11,7±2,53* |
7,75±2,19** • |
|
pNN50n, мс |
32,7±3,64 |
25,3±2,81** |
14,9±2,88*** •• |
|
Note: * р <0,05; **р < 0,01; ***р < 0,001 in relation to subgroup A; • р <0,05; ••р < 0,01 values between B and C subgroups. |
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In general, with augmentation of age, depression of all time indicators of HRV took place (the table No. 2.). Values of indicators RMSSD and pNN50 characterizing a parasympathetic link of a vegetative nervous system in all age groups were authentically above at night, than for the day period of days (in And subgroup — RMSSDD — 37,0±3,93 ms and RMSSDN — 58,50±5,25 ms, rnn50d-15,9±2.89 and rnn50n-32,7±3,64; in B subgroup — RMSSDD — 20,3±4,12 ms and RMSSDN of-36,0±5,3 ms, rnn50d — 11,7±2,53 and rnn50n-25,3±2,81 (p<0,01); in C subgroup — RMSSDD — 19,6±4,14 ms and RMSSDN — 29,5±5,7 ms, pnn50d — 7,75±2,19 and pnn50n-14,9±28,8) (p<0,001).
Between examined B and C age groups, difference were taped only for indicators of mRR, SDANN and pNN50, at the same time, the level of reliability was lower, than between surveyed A and B subgroup (р <0,05).
Table 3
Average values of frequency domain indicators of HRV at healthy people taking into account their age (M±m)
|
Indicator |
Age category (n=33) |
||
|
(А)25–44y (n=12) |
(В) 44–60 y (n=11) |
(С) over 60 y (n=10) |
|
|
ТРмс2 |
3763,1 ±182,65 |
3020,1±191,37* |
21828,8±186,17***•• |
|
VLF, мс2 |
2249,9±152,19 |
1463,2±148,32* |
1197,2±129,24*** |
|
LF, мс2 |
792,8±30,51 |
681,1±22,46** |
580,6±19,55***•• |
|
HF, мс2 |
490,6±15,58 |
428,4±16,10* |
375,8±16,4 ***• |
|
LF/HF |
1,75±0,16 |
1,68±0,15 |
1,77±0,17 |
|
LFn, n.u. |
71,2±1,48 |
76,5±1,5* |
68,8±1,90***• |
|
HFn, n.u. |
35,7±1,47 |
30,7±1,43* |
24,5±1,51**• |
|
Note: * р <0,05; **р < 0,01; ***р < 0,001 in relation to subgroup А; • р <0,05; ••р < 0,01 values between B and C subgroups. |
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In the analysis of frequency indicators of HRV it is noticed that with age at healthy persons depression of absolute power of VLF, LF and HF components, and as a result of it, the general power of a range of TP (3763,1±182,65 ms2 — in A subgroup, 3020,1±191,37 ms2 in B subgroup (р<0,05) and 2828,8±186,17 ms2 — in C subgroup takes place (р<0,01)).
In difference from persons of young age (A subgroup) in subgroup of patients of middle age (B subgroup) depression of the powers characterizing sympathetic influence of VNS became perceptible. Depression of indicators of VLF for 50,4 %, by LF for 11,0 % (р<0,05) which were also followed by decrease of powers of high frequencies of HF by 14,5 % and HFn by 16,7 % is taped (р<0,05). In spite of the fact that frequency indicators of HRV decreased with augmentation of age, differences of values of a ratio of LF/HF had no reliable differences and were comparable.
Table 4
Average values of frequency domain indicators of HRV at healthy people during the day time (M±m)
|
Indicator |
(А)25–44 y (n=12) |
(В) 44–60 y (n=11) |
(С) over 60 y (n=10) |
|
ТРd, мс2 |
3104,2±143,8 |
2747,3±136,2* |
2255,5±122,9**• |
|
ТРn, мс2 |
3721,9±179,75 |
2544,1 ±135,29** |
1831,3±150,27***• |
|
VLFd, мс2 |
2151,1+141,01 |
1294,6±156,57** |
1289,2±140,95** |
|
VLFn, мс2 |
2523,9±130,17 |
1785,6±149,47* |
1566,2±134,06** |
|
LFd, мс2 |
732,7±29,27 |
373,2±24,25** |
295,9±27,43***• |
|
LFn, мс2 |
812,5±27,66 |
551,7±24,70** |
437,0±29,17***•• |
|
HFd, мс2 |
227,1 ±16,81 |
83,6±18,26*** |
70,7±21,52*** |
|
HFn, мс2 |
417,8±15,4 |
219,9±16,7*** |
144,2±14,18***•• |
|
LFd/HFd |
4,6±0,20 |
5,3±0,17 |
4,9±0,19 |
|
LFn/HFn |
2,2±0,19 |
3,0±0,18 |
3,5±0,21 |
|
LFnd, n.u. |
74,9±1,5 |
79,3±1,65 |
77,7±1,43 |
|
LFn_n, n.u. |
62,7±1,63 |
69,7±1,58* |
70,3±1,72* |
|
HFnd, n.u. |
20,1±1,48 |
17,0±1,63* |
18,7±1,71* |
|
HFn_n, n.u. |
35,0±2,2 |
28,3±1,9* |
26,6±1,84* |
|
Note: * р <0,05; **р < 0,01; ***р < 0,001 in relation to subgroup А; • р <0,05; ••р < 0,01 values between B and C subgroups. |
|||
Between examined B and C subgroups were differences only of TP ratios concerned (3020,1±191,37 and 21828,8±186,17; р<0,01), LF (681,1±22,46 and 580,6±19,55; р<0,01), HF (428,4±16,10 and 375,8±16,4; р<0,05), LFn (76,5±1,5 and 68,8±1,90; р<0,05) and HFn (30,7±1,43 and 24,5±1,51; р<0,05).
Differences on all indicators of the low-frequency and high-pitched making HRV expressed in the normalized units were observed between A and B subgroup 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.
Thus, it is possible to conclude that, more, changes of indicators of HRV took place between A and B subgroup of examined. Differences between examined B and C subgroup concerned only separate time and frequency indicators of HRV.
Conclusion: Thus, with age from 20 to over 65 years become perceptible gradual depression of HRV. Considering that on this background the average cardiac contractions rate 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 depression of the general power of a range of HRV due to the prevailing depression low of LF and high-pitched HF of a component is bound. As depression of LF and NF happens synchronously, the relation of LF/HF changes a little.
