Chinushi M, Aizawa Y, Funazaki T, Tamura M, Shibata A
First Department of Internal Medicine, Niigata University School of Medicine, Japan.
Pacing Clin Electrophysiol. 1992 May;15(5):756-61. doi: 10.1111/j.1540-8159.1992.tb06842.x.
In a patient with sustained ventricular tachycardia, we obtained two different paced QRS morphologies from a single pacing site. In one QRS morphology the stimulus to the QRS complex was long, 150 msec, and in the other it was 100 msec. At the paced cycle length of 600 msec and the stimulus output of 4 V, one QRS morphology with the stimulus to the onset of QRS activation (St-QRS) interval of 150 msec was observed. At the paced cycle length of 400 msec, the other QRS morphology with a St-QRS interval of 100 msec was observed alternatively with the former. At the paced cycle length of 353 msec or 316 msec, the latter with a shorter St-QRS interval was exclusively observed. When the stimulus output was increased from 4 to 10 V, keeping with the paced cycle length at 400 msec, the St-QRS interval was shortened from 100 to 80 msec. For the two QRS morphologies with two St-QRS intervals, two slowly conducting pathways would be responsible. The site of the block in the faster pathway must be located at the proximity of the pacing site and the conduction at a shorter paced cycle length would be explained by "supernormal conduction."
在一名持续性室性心动过速患者中，我们从单个起搏部位获得了两种不同的起搏QRS形态。在一种QRS形态中，刺激至QRS波群的时间较长，为150毫秒，而在另一种形态中为100毫秒。在起搏周期长度为600毫秒且刺激输出为4伏时，观察到一种QRS形态，其刺激至QRS激活起始（St-QRS）间期为150毫秒。在起搏周期长度为400毫秒时，交替观察到另一种St-QRS间期为100毫秒的QRS形态。在起搏周期长度为353毫秒或316毫秒时，仅观察到后者，其St-QRS间期较短。当刺激输出从4伏增加到10伏，同时起搏周期长度保持在400毫秒时，St-QRS间期从100毫秒缩短至80毫秒。对于具有两个St-QRS间期的两种QRS形态，两条缓慢传导路径可能起作用。较快路径中的阻滞部位必须位于起搏部位附近，且较短起搏周期长度下的传导可通过“超常传导”来解释。
