Zaidi M, Robert A, Fesler R, Derwael C, Brohet C
Division of Cardiology, Cliniques Universitaires Saint Luc, University of Louvain Medical School, Brussels, Belgium.
Eur Heart J. 1997 Jul;18(7):1129-34. doi: 10.1093/oxfordjournals.eurheartj.a015408.
Increased dispersion of ventricular repolarization has been shown to be a marker for increased risk of ventricular tachyarrhythmias in various cardiac disorders. The present study is aimed at comparing the values of four dispersion indices in four clinical groups: normal subjects (n = 23), patients with intraventricular conduction defects (QRS > 0.12 s) without underlying cardiac disease (n = 30), patients with dilated cardiomyopathy (n = 36), and patients with both dilated cardiomyopathy and ventricular conduction defects (n = 18).
On an averaged cycle from a 10 s record of 15 simultaneous leads (12-lead ECG and XYZ leads), and after interactive editing, four intervals were computed: JTapex, JTend, QTapex and QTend. For each interval, the dispersion is defined as the difference between the maximal and minimal values across the 15 leads.
The mean values of all four dispersion indices were significantly smaller in the normal group than in the three other groups (P < 0.001). Among patients with dilated cardiomyopathy, those with intraventricular conduction defects had significantly higher dispersion values than those without, even disregarding the QRS duration (P < 0.01). Thus, patients with both dilated cardiomyopathy and ventricular conduction defects have larger dispersion values than patients with ventricular conduction defects alone (P < 0.01) and than those with dilated cardiomyopathy without intraventricular conduction defects.
Dispersion of ventricular repolarization is increased in patients with dilated cardiomyopathy, especially in those with ventricular conduction defects, suggesting that they are at higher risk of arrhythmic events.
心室复极离散度增加已被证明是各种心脏疾病中心室快速性心律失常风险增加的一个标志。本研究旨在比较四个临床组中四个离散度指标的值：正常受试者（n = 23）、无潜在心脏疾病的室内传导阻滞患者（QRS > 0.12 s）（n = 30）、扩张型心肌病患者（n = 36）以及同时患有扩张型心肌病和室内传导阻滞的患者（n = 18）。
从15个同步导联（12导联心电图和XYZ导联）的10 s记录的平均心动周期中，经过交互式编辑后，计算四个间期：JT峰、JT末、QT峰和QT末。对于每个间期，离散度定义为15个导联中最大值与最小值之间的差值。
正常组中所有四个离散度指标的平均值均显著低于其他三组（P < 0.001）。在扩张型心肌病患者中，即使不考虑QRS时限，有室内传导阻滞的患者的离散度值也显著高于无室内传导阻滞的患者（P < 0.01）。因此，同时患有扩张型心肌病和室内传导阻滞的患者的离散度值高于仅患有室内传导阻滞的患者（P < 0.01），也高于无室内传导阻滞的扩张型心肌病患者。
扩张型心肌病患者，尤其是伴有室内传导阻滞的患者，心室复极离散度增加，提示他们发生心律失常事件的风险更高。
