Yaghini Bonabi Safa, El-Hamad Fatima, Müller Alexander, Dommasch Michael, Steger Alexander, Schmidt Georg, Baumert Mathias
School of Electrical and Electronic Engineering, The University of Adelaide, SA 5005, Australia.
Physiol Meas. 2016 Nov;37(11):1925-1933. doi: 10.1088/0967-3334/37/11/1925. Epub 2016 Sep 28.
Beat-to-beat variability of the QT interval (QTV) measured on surface ECG has emerged as a potential marker for ventricular repolarization instability and has been used along with heart rate variability (HRV) to predict arrhythmic risk. Since measurement modalities of QTV have not been standardized, the objective of this study was to investigate the effect of ECG recording duration on QTV as well as HRV. Using a database of 30 min ECG recorded from 500 patients with acute myocardial infraction during rest, we extracted RR and QT interval time series and estimated different HRV and QTV metrics over windows of varying length. Analysis of variance (ANOVA) and intra-class correlation analyses were computed to investigate the effect of recording length on consistency and short-term reproducibility of HRV and QTV variables. Good consistency (non-significant ANOVA results) and short-term reproducibility (intra-class correlation coefficients >0.8) were demonstrated for all but standard deviation based metrics when at least 200 beats were included in the estimation. In conclusion, QTV can be quantified from resting ECG with good short-term consistency and reproducibility that is comparable to that of HRV.
体表心电图测量的QT间期逐搏变异性（QTV）已成为心室复极不稳定的潜在标志物，并已与心率变异性（HRV）一起用于预测心律失常风险。由于QTV的测量方式尚未标准化，本研究的目的是调查心电图记录时长对QTV以及HRV的影响。利用从500例急性心肌梗死患者静息时记录的30分钟心电图数据库，我们提取了RR和QT间期时间序列，并在不同长度的窗口上估计了不同的HRV和QTV指标。计算方差分析（ANOVA）和组内相关分析，以研究记录长度对HRV和QTV变量的一致性和短期可重复性的影响。当估计中至少包含200次心搏时，除基于标准差的指标外，所有指标均显示出良好的一致性（ANOVA结果无统计学意义）和短期可重复性（组内相关系数>0.8）。总之，QTV可从静息心电图中进行量化，具有良好的短期一致性和可重复性，与HRV相当。
