Xu Z, Gulrajani R M, Molin F, Lorange M, Dubé B, Savard P, Nadeau R A
Research Center, Hôpital du Sacré-Coeur de Montréal, Québec, Canada.
J Electrocardiol. 1996 Apr;29(2):73-90. doi: 10.1016/s0022-0736(96)80117-8.
With the advent of catheter ablation procedures, it has become an important goal to predict noninvasively the site of origin of ventricular tachycardia. Site classifications based on the observed body surface potential maps (BSPMs) during ventricular endocardial pacing, as well as on the patterns of the QRS integrals of these maps, have been suggested. The goals of this study were to verify these maps and their QRS integral patterns via simulation using a computer heart model with realistic geometry and to determine whether the model could improve clinical understanding of these ectopic patterns. Simulation was achieved by initiating excitation of the heart model at different endocardial sites and their overlying epicardial counterparts. This excitation propagated in anisotropic fashion in the myocardium. Retrograde excitation of the model's His-Purkinje conduction system was necessary to obtain realistic activation durations. Simulated BSPMs, computed by placing the heart model inside a numerical torso model, and their QRS integrals were close to those observed clinically. Small differences in QRS integral map patterns and in the positions of the QRS integral map extrema were noted for endocardial sites in the left septal and anteroseptal regions. The simulated BSPMs during early QRS for an endocardial site and its epicardial counterpart tended to be mirror images about the zero isopotential contour, exchanging positive and negative map regions. The simulation results attest to the model's ability to reproduce accurately clinically recorded body surface potential distributions obtained following endocardial stimulation. The QRS integral maps from endocardial sites in the left septal and anteroseptal regions were the most labile, owing to considerable cancellation effects. Conventional BSPMs can be useful to help distinguish between endocardial and epicardial ectopic sites.
随着导管消融手术的出现，无创预测室性心动过速的起源部位已成为一个重要目标。基于心室心内膜起搏期间观察到的体表电位图（BSPM）以及这些图的QRS积分模式，已经提出了部位分类方法。本研究的目的是通过使用具有真实几何形状的计算机心脏模型进行模拟来验证这些图及其QRS积分模式，并确定该模型是否可以增进对这些异位模式的临床理解。通过在不同的心内膜部位及其对应的心外膜部位引发心脏模型的兴奋来实现模拟。这种兴奋在心肌中以各向异性方式传播。为了获得真实的激活持续时间，模型的希氏-浦肯野传导系统的逆行兴奋是必要的。通过将心脏模型放置在数字躯干模型中来计算模拟的BSPM，其QRS积分与临床观察到的结果接近。对于左间隔和前间隔区域的心内膜部位，QRS积分图模式和QRS积分图极值位置存在微小差异。心内膜部位及其心外膜对应部位在QRS早期的模拟BSPM往往是关于零等电位线的镜像，正负极性的图区域相互交换。模拟结果证明了该模型能够准确再现心内膜刺激后临床记录的体表电位分布。由于显著的抵消效应，左间隔和前间隔区域的心内膜部位的QRS积分图最不稳定。传统的BSPM有助于区分心内膜和心外膜异位部位。
