Horie Takuya, Burioka Naoto, Amisaki Takashi, Shimizu Eiji
Division of Clinical Laboratory, Tottori University Hospital, Yonago 683-8504, Japan.
†Department of Pathological Science and Technology, School of Health Science, Tottori University Faculty of Medicine, Yonago 683-8503, Japan.
Yonago Acta Med. 2018 Mar 28;61(1):49-57. doi: 10.33160/yam.2018.03.007. eCollection 2018 Mar.
Atrial fibrillation (AF) is an arrhythmia commonly encountered in clinical practice. There is a high risk of thromboembolism in patients with AF. Nonlinear analyses such as electroencephalogram (EEG), electrocardiogram (ECG), and respiratory movement have been used to quantify biological signals, and sample entropy (SampEn) has been employed as a statistical measure to evaluate complex systems. In this study, we examined the values of SampEn in ECG signals for patients with and without AF to measure the regularity and complexity.
ECG signals of lead II were recorded from 34 subjects without arrhythmia and 15 patients with chronic AF in a supine position. The ECG signals were converted into time-series data and SampEn was calculated.
The SampEn values for the group without arrhythmia were 0.252 ± 0.114 [time lag (τ) = 1] and 0.533 ± 0.163 (τ = 5), and those for the chronic AF group were 0.392 ± 0.158 (τ = 1) and 0.759 ± 0.246 (τ = 5). The values of SampEn were significantly higher in the group with chronic AF than in the group without arrhythmia ( < 0.01 for τ = 1, < 0.004 for τ = 5). The constructed three-dimensional vectors were plotted in time-delayed three-dimensional space. We used time lags of τ = 5 and τ = 1. The shape of the loops of the three-dimensional space was better for τ = 5.
The values of SampEn from ECG for chronic AF patients were higher than for subjects without arrhythmia, suggesting greater complexity for the time-series from chronic AF patients. SampEn is considered a new index for evaluating complex systems in ECG.
心房颤动（AF）是临床实践中常见的心律失常。AF患者存在较高的血栓栓塞风险。诸如脑电图（EEG）、心电图（ECG）和呼吸运动等非线性分析已被用于量化生物信号，样本熵（SampEn）已被用作评估复杂系统的统计量度。在本研究中，我们检测了AF患者和非AF患者心电图信号中的SampEn值，以测量其规律性和复杂性。
在34名无心律失常的受试者和15名慢性AF患者仰卧位时记录II导联心电图信号。将心电图信号转换为时间序列数据并计算SampEn。
无心律失常组的SampEn值在时间延迟（τ）=1时为0.252±0.114，在τ=5时为0.533±0.163；慢性AF组的SampEn值在τ=1时为0.392±0.158，在τ=5时为0.759±0.246。慢性AF组的SampEn值显著高于无心律失常组（τ=1时P<0.01，τ=5时P<0.004）。在时间延迟三维空间中绘制构建的三维向量。我们使用了τ=5和τ=1的时间延迟。τ=5时三维空间环的形状更好。
慢性AF患者心电图的SampEn值高于无心律失常的受试者，表明慢性AF患者的时间序列更复杂。SampEn被认为是评估心电图复杂系统的一个新指标。
