Liu Z W, Jia P, Ershler P R, Taccardi B, Lux R L, Khoury D S, Rudy Y
Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106-7207, USA.
J Cardiovasc Electrophysiol. 1997 Apr;8(4):415-31. doi: 10.1111/j.1540-8167.1997.tb00807.x.
Mapping endocardial activation and repolarization processes is critical to the study of arrhythmias and selection of therapeutic procedures. Previously, we developed methodology for reconstructing endocardial potentials from potentials measured with a noncontact, intracavitary probe. This study further develops and evaluates the ability of the approach to provide detailed information on the spatiotemporal characteristics of the activation process. Specifically, we reconstructed endocardial electrograms and isochrones throughout the activation process over the entire endocardium during a single beat.
Cavity potentials were measured with a 65-electrode probe placed inside an isolated canine left ventricle. Endocardial potentials were measured simultaneously using 52 electrodes. Potentials were acquired during subendocardial pacing from different locations. Computed electrograms at various sites closely resemble the measured electrograms (correlation coefficient > 0.9 at 60% of the electrodes). Computed isochrones locate subendocardial pacing sites with 10-mm accuracy. Two pacing sites, 17 mm apart, were resolved. Critical regions, such as areas of isochrone crowding, were accurately reconstructed.
Results indicate the applicability of the approach to mapping the cardiac excitation process on a beat-by-beat basis without occluding the ventricle. The ability of locating electrical events (e.g., single or multiple initiation sites) is demonstrated. Importantly, the method is shown to be capable of reconstructing electrograms over the entire endocardium and determining nonuniformities of activation spread (e.g., areas of slow conduction). These capabilities are important to clinical application in the electrophysiology laboratory and experimental studies of arrhythmias in the intact animal.
绘制心内膜激活和复极化过程对于心律失常的研究以及治疗方案的选择至关重要。此前，我们开发了一种从非接触式心腔内探头测量的电位重建心内膜电位的方法。本研究进一步发展并评估了该方法提供激活过程时空特征详细信息的能力。具体而言，我们在单次心跳期间重建了整个心内膜在激活过程中的心内膜电图和等时线。
使用置于离体犬左心室内的65电极探头测量心腔电位。同时使用52个电极测量心内膜电位。在不同位置进行心内膜下起搏时采集电位。不同部位计算得到的电图与测量得到的电图非常相似（60%的电极处相关系数>0.9）。计算得到的等时线定位心内膜下起搏部位的精度为10毫米。分辨出了相距17毫米的两个起搏部位。准确重建了关键区域，如等时线密集区域。
结果表明该方法适用于逐搏绘制心脏兴奋过程且不阻塞心室。证明了其定位电事件（如单个或多个起始部位）的能力。重要的是，该方法能够重建整个心内膜的电图并确定激活传播的不均匀性（如缓慢传导区域）。这些能力对于电生理实验室的临床应用以及完整动物心律失常的实验研究具有重要意义。
