Department of Electrical Engineering, ESAT-SCD, Katholieke Universiteit Leuven, Belgium.
Med Eng Phys. 2012 Jan;34(1):108-17. doi: 10.1016/j.medengphy.2011.07.004. Epub 2011 Aug 17.
Heart rate variability (HRV) is used as a marker of autonomic modulation of heart rate. Nonlinear HRV parameters providing information about the scaling behaviour or the complexity of the cardiac system were included. In addition, the chaotic behaviour was quantified by means of the recently developed numerical noise titration technique. 24h Holter recordings of a large healthy population (N=276, 141 males, 18-71 years of age) were available. The goal was to investigate the influence of gender, age and day-night variation on these nonlinear HRV parameters. Numerical titration yielded similar information as other nonlinear HRV parameters do. However, it does not require long and cleaned data and therefore applicable on short (5min) noisy time series. A higher nonlinear behaviour was observed during the night (NLdr; day: 50.8±19.6%, night: 59.1±19.5%; P<0.001) while nonlinear heart rate fluctuations decline with increasing age (NLdr; Pearson correlation coefficient r between -0.260 and -0.319 dependent on gender and day or night, all P<0.01). A clear circadian profile could be found for almost every parameter, showing in particular which changes occur during the transition phases of waking up and going to sleep. Our results support the involvement of the autonomic nervous system in the generation of nonlinear and complex heart rate dynamics.
心率变异性（HRV）被用作心率自主调节的标志物。本研究纳入了提供有关心脏系统缩放行为或复杂性信息的非线性 HRV 参数。此外，还通过最近开发的数值噪声滴定技术来量化混沌行为。有大量健康人群（N=276，男性 141 人，年龄 18-71 岁）的 24 小时动态心电图记录可用。研究目的是调查性别、年龄和昼夜变化对这些非线性 HRV 参数的影响。数值滴定提供了与其他非线性 HRV 参数相似的信息。然而，它不需要长而干净的数据，因此适用于短（5 分钟）嘈杂的时间序列。夜间观察到更高的非线性行为（NLdr；白天：50.8±19.6%，夜间：59.1±19.5%；P<0.001），而非线性心率波动随年龄增长而下降（NLdr；Pearson 相关系数 r 在-0.260 到-0.319 之间，取决于性别和白天或夜间，所有 P<0.01）。几乎每个参数都有明确的昼夜节律特征，特别是在醒来和入睡过渡阶段发生的变化。我们的结果支持自主神经系统参与非线性和复杂心率动力学的产生。
