Lippman N, Stein K M, Lerman B B
Department of Medicine, New York Hospital-Cornell Medical Center, New York 10021.
J Electrocardiol. 1993;26 Suppl:14-9.
Heart rate variability (HRV) analysis is a technique that uses the beat-to-beat variations in RR intervals as a measure of the level of activity of the autonomic nervous system. However, the presence of ectopic beats can alter measures of HRV by introducing mathematical artifact and thus, prevent accurate determinations of HRV. Simple exclusion of those portions of data that contain ectopy from analysis inappropriate because (1) it can lead to a substantial reduction in the amount of data available for analysis and (2) if the presence (and frequency) of ectopic beats is correlated with specific alterations in autonomic tone, then the utilization of only ectopy-free data for analysis will lead to bias in the measures. For this reason, methods for the correction of ectopic beats have been devised and applied in the determination of HRV. The authors therefore propose a new method for the correction of ectopic beats: nonlinear predictive interpolation. Using the fact that beat-to-beat changes in heart rate occur in a deterministic fashion as the only assumption, the authors apply the methods of chaos theory in order to locate ectopy-free portions of the RR interval sequence that describe trajectories in phase space that are locally similar to that of the ectopy-containing segments. The authors then determine which of these trajectories most closely approximates that of a particular ectopy-containing segment, and use it to determine replacement RR intervals for the ectopic beats.
心率变异性（HRV）分析是一种利用RR间期逐搏变化作为自主神经系统活动水平衡量指标的技术。然而，异位搏动的存在会通过引入数学伪迹改变HRV的测量值，从而妨碍对HRV的准确测定。简单地从分析中排除包含异位搏动的数据部分是不合适的，原因如下：（1）这可能导致可用于分析的数据量大幅减少；（2）如果异位搏动的存在（及其频率）与自主神经张力的特定改变相关，那么仅使用无异位搏动的数据进行分析将导致测量结果出现偏差。因此，已经设计出用于校正异位搏动的方法并应用于HRV的测定。作者因此提出了一种校正异位搏动的新方法：非线性预测插值法。作者仅基于心率逐搏变化以确定性方式发生这一假设，应用混沌理论方法来定位RR间期序列中无异位搏动的部分，这些部分描述的相空间轨迹在局部上与包含异位搏动的片段相似。然后，作者确定这些轨迹中哪一个最接近特定包含异位搏动片段的轨迹，并使用它来确定异位搏动的替代RR间期。
