Okumura K, Horio Y, Matsuyama K, Araki S
Jpn Circ J. 1983 Jun;47(6):661-70. doi: 10.1253/jcj.47.661.
We examined electrophysiological properties of the ischemic myocardium of the canine heart. Multiple bipolar electrodes for stimulation or for recording electrograms were placed on the epicardial surface and at the endocardium of the ventricle. The time course of changes in excitability threshold, in effective refractory period and in local conduction time during ischemia was estimated at the epicardial and endocardial sides of the central ischemic zone, at the epicardial side of the peripheral ischemic zone and at both sides of the normal zone. Soon after left anterior descending coronary artery occlusion, a rise of excitability threshold, a lengthening of effective refractory period and a prolongation of conduction time consistently occurred in all portions of the ischemic zone. The degree of changes, however, was not uniform: it was greater at the epicardial side of the central ischemic zone. In most experiments, the changes reached maximum within 10 min after occlusion. Then, altered electrophysiological properties recovered to some extent or stabilized. The results indicate that electrophysiological properties deteriorate momentarily after coronary occlusion but then recover or stabilize, and that their changes during acute ischemia are not uniform in the ischemic region but severer at the central zone and epicardial side.
我们研究了犬心脏缺血心肌的电生理特性。用于刺激或记录心电图的多个双极电极置于心室的心外膜表面和心内膜。在中央缺血区的心外膜侧和心内膜侧、外周缺血区的心外膜侧以及正常区两侧，估计缺血期间兴奋性阈值、有效不应期和局部传导时间的变化时间进程。左冠状动脉前降支闭塞后不久，缺血区所有部位均持续出现兴奋性阈值升高、有效不应期延长和传导时间延长。然而，变化程度并不一致：中央缺血区的心外膜侧变化更大。在大多数实验中，变化在闭塞后10分钟内达到最大值。然后，改变的电生理特性在一定程度上恢复或稳定。结果表明，冠状动脉闭塞后电生理特性瞬间恶化，但随后恢复或稳定，并且在急性缺血期间其变化在缺血区域并不均匀，中央区和心外膜侧更严重。
