Oster H S, Taccardi B, Lux R L, Ershler P R, Rudy Y
Cardiac Bioelectricity Research and Training Center, Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106-7207, USA.
Circulation. 1997 Aug 5;96(3):1012-24. doi: 10.1161/01.cir.96.3.1012.
The goal of noninvasive electrocardiographic imaging (ECGI) is to determine electric activity of the heart by reconstructing maps of epicardial potentials, excitation times (isochrones), and electrograms from data measured on the body surface.
Local electrocardiac events were initiated by pacing a dog heart in a human torso-shaped tank. Body surface potential measurements (384 electrodes) were used to compute epicardial potentials noninvasively. The accuracy of reconstructed epicardial potentials was evaluated by direct comparison to measured ones (134 electrodes). Protocols included pacing from single sites and simultaneously from two sites with various intersite distances. Body surface potentials showed a single minimum for both single- and double-site pacing (intersite distances of 52, 35, and 17 mm). Noninvasively reconstructed epicardial electrograms, potentials, and isochrones closely approximated the measured ones. Single pacing sites were reconstructed to within < or = 10 mm of their measured positions. Dual sites were located accurately and resolved for the above intersite distances. Regions of sparse and crowded isochrones, indicating spatial nonuniformities of epicardial activation spread, were also reconstructed.
The study demonstrates that ECGI can reconstruct epicardial potentials, electrograms, and isochrones over the entire epicardial surface during the cardiac cycle. It can provide detailed information on local activation of the heart noninvasively. Its uses could include localization of cardiac electric events (eg, ectopic foci), characterization of nonuniformities of conduction, characterization of repolarization properties (eg, dispersion), and mapping of dynamically changing arrhythmias (eg, polymorphic VT) on a beat-by-beat basis.
无创心电图成像(ECGI)的目标是通过从体表测量的数据重建心外膜电位图、兴奋时间(等时线)和心电图来确定心脏的电活动。
在一个人体躯干形状的水箱中对犬心脏进行起搏,引发局部心电事件。利用体表电位测量(384个电极)无创计算心外膜电位。通过与测量值(134个电极)直接比较来评估重建心外膜电位的准确性。方案包括从单个部位起搏以及从两个部位同时起搏,两个起搏部位之间有不同的距离。无论是单部位起搏还是双部位起搏(部位间距离分别为52、35和17毫米),体表电位均显示出单一最小值。无创重建的心外膜心电图、电位和等时线与测量值非常接近。单个起搏部位重建后的位置与测量位置的偏差在≤10毫米以内。对于上述部位间距离,双部位的定位准确且可分辨。还重建了等时线稀疏和密集的区域,这些区域表明心外膜激动传播的空间不均匀性。
该研究表明,ECGI能够在心动周期内重建整个心外膜表面的心外膜电位、心电图和等时线。它能够无创地提供关于心脏局部激动的详细信息。其用途可能包括心脏电事件(如异位灶)的定位、传导不均匀性的特征描述、复极特性(如离散度)的特征描述以及逐搏绘制动态变化的心律失常(如多形性室性心动过速)。