Savard P, Ackaoui A, Gulrajani R M, Nadeau R A, Roberge F A, Guardo R, Dube B
J Electrocardiol. 1985 Jul;18(3):211-21. doi: 10.1016/s0022-0736(85)80045-5.
The accuracy of different computation techniques for the non-invasive localization of cardiac ectopic activity was evaluated. Body surface potentials were recorded from 63 leads in 14 patients with implanted pacemakers. The location, orientation and magnitude of a single moving dipole (SMD) were computed from the first eight terms of a truncated multipole expansion estimated from the body surface potentials. The SMD trajectories obtained during the QRS complex were plotted along with the heart outlines and pacing leads obtained independently from chest x-rays. The origin of the SMD trajectories was compared to the position of the pacing lead to evaluate the accuracy of the SMD. The optimum computation technique used a least-squares (LS) estimation of the multipole expansion truncated at 15 multipoles, in conjunction with a torso model that included regions of lower conductivity representing the lungs. With this method, the SMD trajectories originated near the pacing lead (25 +/- 12 mm) and adequately represented the progression of the ectopic wavefront across the entire heart silhouette. With the LS techniques using 8 or 24 multipoles, the spans of the trajectories were respectively too short, or too long to cover the heart, and the average distance between the SMD at QRS onset and the pacing lead was larger. With a surface integration technique, the SMD-pacing lead distances were similar, both for a finite homogeneous torso model with a fixed geometry, as well as for torso models adapted to the torso geometry of each patient. The SMD was found adequate to represent the progression of an ectopic wavefront, and to localize its origin in man.
评估了用于心脏异位活动非侵入性定位的不同计算技术的准确性。对14例植入起搏器患者的63个导联记录体表电位。根据从体表电位估计的截断多极展开的前八项计算单个移动偶极子（SMD）的位置、方向和大小。将QRS波群期间获得的SMD轨迹与独立于胸部X光获得的心脏轮廓和起搏导线一起绘制。将SMD轨迹的起源与起搏导线的位置进行比较，以评估SMD的准确性。最佳计算技术使用截断为15个多极的多极展开的最小二乘（LS）估计，并结合包含代表肺部的低电导率区域的躯干模型。使用这种方法，SMD轨迹起源于起搏导线附近（25±12mm），并充分代表了异位波前在整个心脏轮廓上的进展。使用8个或24个多极的LS技术时，轨迹的跨度分别太短或太长而无法覆盖心脏，并且QRS波起始时SMD与起搏导线之间的平均距离更大。使用表面积分技术时，对于具有固定几何形状的有限均匀躯干模型以及适应每个患者躯干几何形状的躯干模型，SMD与起搏导线的距离相似。发现SMD足以代表异位波前的进展，并在人体中定位其起源。
