Zhang Yijie, Bao Mingwei, Dai Mingyan, Zhong Hui, Li Yan, Tan Tuantuan
Department of Cardiology, Wuhan University, Renmin Hospital.
Circ J. 2014;78(12):2942-9. doi: 10.1253/circj.cj-14-0697. Epub 2014 Oct 14.
QT hysteresis phenomenon exists in healthy subjects, and is more exaggerated in patients with coronary artery disease (CAD) and long QT syndrome. The purpose of this study was to establish an appropriate method to evaluate the magnitude of QT hysteresis, and assess the value of QT hysteresis index in the treadmill exercise test (TET) in predicting CAD. METHODS AND RESULTS: A total of 138 subjects with suspected CAD and referred for TET and selective coronary angiography (SCA) were divided into positive (n=77) and negative (n=61) SCA groups. Dynamic ECG were recorded during TET. QT/RR curves were constructed and QTp (Q-Tpeak) and QTe (Q-Tend) hysteresis indices were calculated for each subject. SYNTAX score in the positive SCA group was determined. The QTp and QTe hysteresis indices in the positive SCA group were significantly higher than in the negative SCA group. The combination of QTe hysteresis index and conventional TET criteria had the highest sensitivity and negative predictive value according to receiver operating characteristic curve, and was an independent predictor on multivariate logistic regression. QT hysteresis indices significantly correlated with SYNTAX score in the positive SCA group.
QTe hysteresis index enhances the specificity of predicting CAD in TET. It improves the diagnostic value of TET for CAD significantly when combined with conventional criteria and is associated with the severity of CAD.
QT 滞后现象存在于健康受试者中，在冠心病（CAD）和长 QT 综合征患者中更为明显。本研究的目的是建立一种评估 QT 滞后幅度的合适方法，并评估跑步机运动试验（TET）中 QT 滞后指数预测 CAD 的价值。方法与结果：总共 138 名疑似 CAD 并接受 TET 和选择性冠状动脉造影（SCA）的受试者被分为 SCA 阳性组（n = 77）和阴性组（n = 61）。在 TET 期间记录动态心电图。构建 QT/RR 曲线，并为每个受试者计算 QTp（Q 波峰时程）和 QTe（Q 波终末时程）滞后指数。确定 SCA 阳性组的 SYNTAX 评分。SCA 阳性组的 QTp 和 QTe 滞后指数显著高于阴性组。根据受试者工作特征曲线，QTe 滞后指数与传统 TET 标准相结合具有最高的敏感性和阴性预测价值，并且在多因素逻辑回归中是独立预测因子。SCA 阳性组中 QT 滞后指数与 SYNTAX评分显著相关。结论：QTe 滞后指数提高了 TET 中预测 CAD 的特异性。当与传统标准结合时，它显著提高了 TET 对 CAD 的诊断价值，并且与 CAD 的严重程度相关。
