Lin J L, Wilber D J, Du D, Pearlman J, Ruskin J N, Garan H
Cardiac Unit, Massachusetts General Hospital, Harvard Medical School, Boston 02114.
Circulation. 1991 Sep;84(3):1319-32. doi: 10.1161/01.cir.84.3.1319.
The precision and limitations of ventricular pacemapping as a method to localize the site of earliest breakthrough of ventricular tachycardia (VT) were investigated in a canine model of experimental myocardial infarction.
Forty-one episodes of VT induced in 10 animals were mapped using a standard grid of 64 endocardial and epicardial bipolar electrodes to determine the site of earliest endocardial or epicardial breakthrough of activation during VT. Each of these 64 recording sites was also used for ventricular pacing during sinus rhythm at cycle lengths comparable to those of the VTs. Orthogonal X, Y, and Z Frank electrocardiographic (ECG) leads were recorded during all episodes of VT and ventricular pacing from all sites after the chest was closed in all animals. Surface ECG waveforms corresponding to each VT and each ventricular pacing were compared pairwise by measuring the Euclidean metric difference between the VT and ventricular pacing vectors with the orthogonal ECG leads as their X, Y, and Z components. The pacing site that generated the vector most similar to VT vector (smallest vectorial difference) was defined as the predicted breakthrough site. This predicted site of breakthrough was identical to the actual site of breakthrough determined by activation sequence mapping during VT for only nine VTs (22%). However, for an additional 27 VTs (66%), the observed and predicted breakthrough locations were at adjacent (1 cm or less apart) recording sites. For five VTs (12%), the two sites were remote, the distance between them exceeding 1 cm.
In this model, locating the breakthrough site by pacemapping is exact in only a small minority of VTs. However, when orthogonal surface ECG leads are used for comparison, pacemapping can predict the site of earliest breakthrough during VT with a 1-cm resolution in the majority of VTs.
在犬实验性心肌梗死模型中，研究了心室起搏标测作为定位室性心动过速（VT）最早激动突破点方法的准确性和局限性。
使用64个心内膜和心外膜双极电极的标准网格对10只动物诱发的41次VT发作进行标测，以确定VT期间最早的心内膜或心外膜激动突破点。在窦性心律期间，以与VT周期长度相当的周期长度，对这64个记录部位中的每一个进行心室起搏。在所有动物胸部闭合后，记录所有VT发作和所有部位心室起搏期间的正交X、Y和Z Frank心电图（ECG）导联。通过测量以正交ECG导联为X、Y和Z分量的VT与心室起搏向量之间的欧几里得度量差异，对每个VT和每个心室起搏对应的表面ECG波形进行两两比较。产生与VT向量最相似向量（最小向量差异）的起搏部位被定义为预测突破点。仅9次VT（22%）的该预测突破点与VT期间通过激动顺序标测确定的实际突破点相同。然而，另外27次VT（66%）的观察到的和预测的突破位置位于相邻（相距1 cm或更小）的记录部位。对于5次VT（12%），两个部位相距较远，它们之间的距离超过1 cm。
在该模型中，通过起搏标测定位突破点仅在少数VT中是准确的。然而，当使用正交表面ECG导联进行比较时，起搏标测可在大多数VT中以1 cm的分辨率预测VT期间最早的突破点。
