Duff H J, Mitchell L B, Gillis A M, Sheldon R S, Chudleigh L, Cassidy P, Chiamvimonvat N, Wyse D G
Department of Medicine, University of Calgary, Foothills Hospital, Alberta, Canada.
Circulation. 1993 Sep;88(3):1054-62. doi: 10.1161/01.cir.88.3.1054.
In vitro studies have reported that beat-to-beat variance in tachycardia cycle length and in conduction and repolarization properties can result in spontaneous termination of reentrant arrhythmias. The purpose of this study was to define the ECG patterns associated with spontaneous termination of ventricular tachycardia in humans late after myocardial infarction.
The QRS durations, QT intervals, and cycle lengths were measured on a beat-to-beat basis during episodes of sustained and spontaneously terminating ventricular tachycardias (VT) induced at antiarrhythmic drug-free and drug-assessment electrophysiological studies. Twenty-six patients were studied. Four categories of inducible ventricular tachycardia were studied: inducible sustained ventricular tachycardia in an antiarrhythmic drug-free state, spontaneously terminating ventricular tachycardia in an antiarrhythmic drug-free state, sustained ventricular tachycardia on antiarrhythmic therapy, and spontaneously terminating ventricular tachycardia on antiarrhythmic therapy. The ECG patterns that were statistically related to spontaneous termination of ventricular tachycardia included impingement of the QTP interval on the tachycardia cycle length (P < .001) both in the presence and absence of drugs, transient shortening of QRS just before termination, and paradoxical prolongation of QTP after abrupt shortening of ventricular tachycardia cycle length. In addition, greater beat-to-beat variances in tachycardia cycle lengths, QT intervals, and QRS durations were statistically associated with spontaneously terminating ventricular tachycardia. These ECG patterns did not occur during sustained episodes of ventricular tachycardia during the antiarrhythmic drug-free state or during ineffective antiarrhythmic drug therapy.
A dynamic interplay between QRS duration, QT interval, and cycle length of tachycardia and their variances are associated with spontaneous termination of ventricular tachycardia in humans late after infarction. This study of ECG changes associated with spontaneous termination of ventricular tachycardia provides insight into potential mechanisms of antiarrhythmic drug efficacy.
体外研究报告称，心动过速周期长度以及传导和复极特性的逐搏变化可导致折返性心律失常的自发终止。本研究的目的是确定心肌梗死后晚期人类室性心动过速自发终止相关的心电图模式。
在无抗心律失常药物和药物评估的电生理研究中诱发的持续性和自发终止的室性心动过速（VT）发作期间，逐搏测量QRS波时限、QT间期和心动周期长度。对26例患者进行了研究。研究了四类可诱发的室性心动过速：无抗心律失常药物状态下可诱发的持续性室性心动过速、无抗心律失常药物状态下自发终止的室性心动过速、抗心律失常治疗时的持续性室性心动过速以及抗心律失常治疗时自发终止的室性心动过速。与室性心动过速自发终止有统计学关联的心电图模式包括：无论有无药物，QTP间期对心动过速周期长度的影响（P <.001）、终止前QRS波短暂缩短以及室性心动过速周期长度突然缩短后QTP的矛盾性延长。此外，心动过速周期长度、QT间期和QRS波时限更大的逐搏变化与自发终止的室性心动过速有统计学关联。这些心电图模式在无抗心律失常药物状态下的持续性室性心动过速发作期间或无效的抗心律失常药物治疗期间未出现。
QRS波时限、QT间期和心动过速周期长度及其变化之间的动态相互作用与心肌梗死后晚期人类室性心动过速的自发终止有关。这项关于与室性心动过速自发终止相关的心电图变化的研究为抗心律失常药物疗效的潜在机制提供了见解。
