1990年,Day等首先提出QT离散度(QTd)的概念,他们将心电图12导联中最长与最短QT间期之差定义为QTd,并认为这是反映心肌区域性复极差异的定量指标,具有预测恶性心律失常及猝死危险性的意义。心肌复极离散是室性心律失常重要的电生理基础,而恶性室性心律失常是严重威胁人类生命的急症,但以往临床上缺乏描述心肌复极异常的简单、无创、有效的指标。所以自从QTd的概念被提出以来,大量的研 In 1990, Day et al first proposed the concept of QTd (QTd). They defined the difference between the longest and shortest QT interval in ECG lead 12 as QTd and considered it as a quantitative indicator of myocardial regional repolarization differences , With the significance of predicting the risk of malignant arrhythmias and sudden death. Myocardial repolarization dispersion is an important electrophysiological basis of ventricular arrhythmia, and malignant ventricular arrhythmia is a serious threat to human life, emergency, but the past lack of clinical description of myocardial repolarization simple, noninvasive and effective indicators. So since the concept of QTd has been proposed, a lot of research