Mehdirad A A, Keim S, Rist K, Mazgalev T, Tchou P
Department of Medicine, University of Pittsburgh School of Medicine, Pennsylvania.
J Am Coll Cardiol. 1994 Jul;24(1):177-84. doi: 10.1016/0735-1097(94)90560-6.
The purpose of this study was to delineate retrograde His-Purkinje system conduction and reentry (V3 phenomenon) during left ventricular extrastimulation and compare them with right ventricular extrastimulation.
The V3 phenomenon has been well described in the past during right ventricular extrastimulation; however, it has not been studied systematically during left ventricular extrastimulation.
Left and right ventricular pacing were performed in 13 patients. Retrograde and anterograde routes of impulse propagation were determined on the basis of the sequence of His (H) and right bundle (RB) potentials, H-RB intervals, as well as the QRS configuration and axis of V3 beats.
During right ventricular pacing, retrograde conduction of V2, when discernible, occurred exclusively through the left bundle at all coupling intervals equal to or shorter than the His-Purkinje relative refractory period, with the exception of two isolated beats. During left ventricular extrastimulation, His bundle activation was through the left bundle in nine patients and through the right or left bundle in three other patients. In one patient, the route could not be determined. The V3 phenomena occurred in eight patients during right ventricular pacing. Seven patients had a left bundle branch block pattern QRS configuration, and one had a right bundle branch block pattern configuration. V3 beats occurred in five patients during left ventricular apex pacing: left bundle branch block pattern configuration in one patient and right bundle branch block pattern configuration in four. In three of these four patients, the reentry was interfascicular and limited to the left bundle branch system.
The left-sided His-Purkinje system is the preferred retrograde route of impulse propagation during both left and right ventricular extrastimulation. Reentry within the His-Purkinje system elicited by right ventricular extrastimulation involves both bundle branches, whereas this reentry tends to occur within the left-sided His-Purkinje system during left ventricular pacing.
本研究旨在描绘左心室额外刺激时逆行希氏-浦肯野系统传导和折返（V3现象），并将其与右心室额外刺激进行比较。
V3现象在过去右心室额外刺激时已有详细描述；然而，在左心室额外刺激时尚未进行系统研究。
对13例患者进行左、右心室起搏。根据希氏（H）和右束支（RB）电位顺序、H-RB间期以及V3波的QRS形态和电轴确定冲动传播的逆行和顺行途径。
右心室起搏时，V2波逆行传导（若可识别）在所有等于或短于希氏-浦肯野相对不应期的耦合间期均仅通过左束支发生，但有两个孤立波除外。左心室额外刺激时，9例患者希氏束激动通过左束支，另外3例患者通过右束支或左束支。1例患者无法确定途径。右心室起搏时8例患者出现V3现象。7例患者QRS形态为左束支传导阻滞图形，1例为右束支传导阻滞图形。左心室心尖起搏时5例患者出现V3波：1例患者为左束支传导阻滞图形，4例为右束支传导阻滞图形。在这4例患者中的3例，折返发生在束支间，局限于左束支系统。
在左、右心室额外刺激时，左侧希氏-浦肯野系统是冲动传播的首选逆行途径。右心室额外刺激引起的希氏-浦肯野系统内折返涉及两个束支，而在左心室起搏时，这种折返倾向于发生在左侧希氏-浦肯野系统内。
