标题：Short-term QT interval variability in patients with coronary artery disease and congestive heart failure: a comparison with healthy control subjects
作者：Li, Yang; Li, Peng; Wang, Xinpei; Karmakar, Chandan; Liu, Changchun; Liu, Chengyu
作者机构：[Li, Yang; Li, Peng; Wang, Xinpei; Liu, Changchun] Shandong Univ, Sch Control Sci & Engn, Jinan, Shandong, Peoples R China.; [Karmakar, Chandan] Dea 更多
通讯作者：Liu, Changchun;Liu, CC
通讯作者地址：[Liu, CC]Shandong Univ, Sch Control Sci & Engn, Jinan, Shandong, Peoples R China.
来源：MEDICAL & BIOLOGICAL ENGINEERING & COMPUTING
关键词：QT interval variability; QT variability index; Sample entropy;; Permutation entropy; Dynamical patterns
摘要：This study aimed to test how different QT interval variability (QTV) indices change in patients with coronary artery disease (CAD) and congestive heart failure (CHF). Twenty-nine healthy volunteers, 29 age-matched CAD patients, and 20 age-matched CHF patients were studied. QT time series were derived from 5-min resting lead-II electrocardiogram (ECG). Time domain indices [mean, SD, and QT variability index (QTVI)], frequency-domain indices (LF and HF), and nonlinear indices [sample entropy (SampEn), permutation entropy (PE), and dynamical patterns] were calculated. In order to account for possible influence of heart rate (HR) on QTV, all the calculations except QTVI were repeated on HR-corrected QT time series (QTc) using three correction methods (i.e., Bazett, Fridericia, and Framingham method). Results showed that CHF patients exhibited increased mean, increased SD, increased LF and HF, decreased T-wave amplitude, increased QTVI, and decreased PE, while showed no significant changes in SampEn. Interestingly, CHF patients also showed significantly changed distribution of the dynamical patterns with less monotonously changing patterns while more fluctuated patterns. In CAD group, only QTVI was found significantly increased as compared with healthy controls. Results after HR correction were in common with those before HR correction except for QTc based on Bazett correctionFig. The framework of this paper. The arrows show the sequential analysis of the data.