Kabir Muammar M, Sedaghat Golriz, Thomas Jason, Tereshchenko Larisa G
Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA.
Portland State University, Portland, OR, USA.
Comput Cardiol (2010). 2016 Sep;2016:289-292. doi: 10.23919/CIC.2016.7868736. Epub 2017 Mar 2.
In this paper we employed joint symbolic dynamics (JSD) approach to study reproducibility of heart rate variability characteristics measured on 2 randomly selected 10-second segments within 3-minute resting orthogonal ECG in 170 healthy participants. First, the ECG R-peaks were detected using parabolic fitting. Second, the respiratory signal was derived from orthogonal ECG X-lead using QRS slopes. Third, time series of R-R intervals and respiratory phases (calculated using Hilbert transform), were transformed into tertiary symbol vectors based on their successive changes and words of length '3' were formed. Bland-Altman analysis was used to assess the agreement between measured log-transformed JSD characteristics of HRV, and their reproducibility. Traditional HRV measures such as RR' interval changes showed a very high reproducibility. However, agreement between two 10-second JSD indices of HRV was low. Interestingly, a significant decrease in low-high alterations of HRV dynamics measured using JSD was observed when respiratory phase transition intervals were excluded (10s: 4.7±9.4 vs. 24.8±21.0%, p<0.0001; 3min: 9.8±8.1 vs. 24.8±12.3%, p<0.0001).
在本文中，我们采用联合符号动力学（JSD）方法，研究了170名健康参与者在3分钟静息正交心电图中随机选取的2个10秒片段上测量的心率变异性特征的可重复性。首先，使用抛物线拟合检测心电图R波峰。其次，利用QRS斜率从正交心电图X导联导出呼吸信号。第三，将R-R间期和呼吸相位（使用希尔伯特变换计算）的时间序列根据其连续变化转换为三级符号向量，并形成长度为“3”的单词。采用布兰德-奥特曼分析评估测量的心率变异性对数转换后的JSD特征之间的一致性及其可重复性。传统的心率变异性测量指标，如RR'间期变化，显示出非常高的可重复性。然而，心率变异性的两个10秒JSD指标之间的一致性较低。有趣的是，当排除呼吸相位转换间期时，观察到使用JSD测量的心率变异性动力学的低-高变化显著降低（10秒：4.7±9.4%对24.8±21.0%，p<0.0001；3分钟：9.8±8.1%对24.8±12.3%，p<0.0001）。
