Jokinen Vesa, Sourander Leif B, Karanko Hannu, Mäkikallio Timo H, Huikuri Heikki V
Division of Cardiology, Department of Medicine, University of Oulu, Finland.
Ann Med. 2005;37(3):206-12. doi: 10.1080/078538905100073331.
Previous cross-sectional studies have suggested that cardiac autonomic regulation, measured as heart rate (HR) variability, is altered upon ageing, and that altered HR variability may predict mortality. However, there are no longitudinal follow-up reports of the changes of HR dynamics in elderly subjects.
AIM & METHOD: This study was designed to examine the longitudinal changes in the spectral, fractal, and complexity measures of HR variability in a random sample of 41 elderly subjects (mean age 69+/-4 years), who underwent repeated 24-hour Holter recordings at the baseline and after 16 years' follow-up. Several cardiovascular risk factors were determined at the baseline.
A time-domain index, standard deviation of N-N intervals (SDNN) (142+/-34 msec versus 133+/-50 msec, not significant (NS)), and the high frequency spectral component of HR variability (219+/-222 msec(2)versus 268+/-287 msec(2), NS) did not change during the follow-up. The low frequency power (LF) of HR variability decreased from 678+/-654 msec(2) to 436+/-651 msec(2) (P<0.01). Among the fractal HR variability indexes, the power-law slope (ss) (-1.31+/-0.20 versus -1.47+/-0.21, P<0.001) and the short-term fractal exponent a1 (1.16+/-0.19 versus 1.06+/-0.18, P<0.01) decreased significantly. Approximate entropy remained unchanged.
The magnitude of total HR variability and the respiratory vagal modulation of HR do not change over time in the elderly. However, the spectral and fractal characteristics of HR behavior still undergo alterations upon ageing.
既往横断面研究提示，以心率（HR）变异性衡量的心脏自主神经调节功能随年龄增长而改变，且HR变异性改变可能预测死亡率。然而，尚无关于老年受试者HR动态变化的纵向随访报告。
本研究旨在对41名老年受试者（平均年龄69±4岁）的随机样本进行HR变异性的频谱、分形和复杂性指标的纵向变化研究，这些受试者在基线时和随访16年后进行了重复的24小时动态心电图记录。在基线时确定了几种心血管危险因素。
时域指标，即N-N间期标准差（SDNN）（142±34毫秒对133±50毫秒，无显著差异（NS）），以及HR变异性的高频频谱成分（219±222毫秒²对268±287毫秒²，NS）在随访期间未发生变化。HR变异性的低频功率（LF）从678±654毫秒²降至436±651毫秒²（P<0.01）。在分形HR变异性指标中，幂律斜率（ss）（-1.31±0.20对-1.47±0.21，P<0.001）和短期分形指数a1（1.16±0.19对1.06±0.18，P<0.01）显著降低。近似熵保持不变。
老年人HR变异性的总量及HR的呼吸性迷走神经调节随时间无变化。然而，HR行为的频谱和分形特征在衰老过程中仍会发生改变。
