AGE-RELATED CHANGES IN HEART RATE VARIABILITY AND THEIR RELATION WITH LEUCOCYTE TELOMERE LENGTH

Abstract

Aim. To assess the relation of age-depended changes in heart rate variability (HRV) with telomere length. With the age, even with no cardiovascular diseases (CVD), there is a decline of HRV which is an indicator of vegetative system condition. The probable mechanism for age-related decrease in HRV might be cellular ageing. One of the markers of cellular ageing is telomere length regarded as a marker of biological age. Material and methods . Totally, 229 persons of age 23-91 y.o. included, with no clinical signs of cardiovascular diseases. All participants underwent the HRV analysis by the data of Holter ECG monitoring and of short ECG recordings supine and upright position by 5 minutes. Telomere length was assessed in leucocytes on genomic desoxyribonucleic acid (DNA) with plymeraze chain reaction real time. The participants were selected to two groups: <60 y.o. and ≥60 y.o. Comparative analysis was done, of the parameters studied, in two age groups, correlational analysis of telomere length with HRV, linear regression analysis and multiple regression. Results. In the group of the older, telomere length was higher than in the younger — 9,90±0,47 units vs 9,65±0,43 units (p<0,001) with close correlation of telomere length with the age (r=-0,32, p<0,05). By the data of linear regression, telomere length is closely related with the mean value of standard deviations of all selected RR intervals for every 5 minutes of 24-hour recording (SDANN), with the power of high-frequency spectrum (HF), relation of lowerand high-frequency waves (L/H) (β=0,36, p=0,006; β=0,39, p=0,004; β=-0,32, р=0,02, resp.). In older persons, in the group of shorter telomeres there were significantly lower values of mean standard deviations for all selected R-R-intervals (SDNN) (111 (94; 126) ms vs 122 (112; 122) ms), mean-square differences between the duratons of the next sinus intervals RR (RMSSD) R-R (RMSSD) — 16 (11; 22) ms vs 22 (17; 25) ms), power of the very low frequency spectrum components (VLF) — 1176 (718; 1453) ms2 vs 1476 (850; 1763) ms2) by the data from Holter ECG, than in the group of longer telomeres (p<0,05). Differences by the shorter recordings supine and upright were not significant. Conclusion. Telomere length is related to the age-relevant HRV changes. Telomere length might be an early predictor of the ageassociated weakening of autonomous regulation of heart functioning and reflect real biological age of vegetative nervous system irrelevant to other cardiovascular risk factors.