家兔急性心肌不完全缺血时心肌不应期兴奋恢复离散度及室颤阈的变化

本实验采用以TP801微处理机为中心的“可编程刺激器”观察了急性不完全缺血心肌不应期、离散度及室颤阈的变化,探讨了室颤的机制。证实:1.不完全缺血心肌不应期呈现出多种变化,其中以不应期延长与缩短同时存在于缺血区为主,即使同一个点,不应期也可能出现延长与缩短交替出现的变化。2.心肌兴奋恢复离散度明显高于缺血前(p<0.01)。3.不完全缺血20分钟内左室室颤阈明显低于缺血前(P<0.01)。根据实验结果认为,急性心肌不完全缺血可能是发生室颤的一个重要原因。

Changesin Refractory Period of Myocardium Dispersion Degree of Recovery of Excitability and Ventricular Firillation Threshold during Acute Incomplate Ischemia of Myocardium in Rabbits

Experiments were performed on 18 rabbits. The left coronary artery was constricted by not occluded to induce ischemia of the left ventilcle. During acute myocardial ischemia refractory period and ventricular fibrillation threshold(VFT)were measured from the ischemic zone.The refractory period of closely adjacent tissues was markedly dispersed and the dispersion degree of recovery of excitability was iucreased. The changes in ventricular fibrillation threshold were characterized by a decrease within 20 min. After the arterial constrictionIt appear that electrophysiological alteration caused by ischemia was an important factor in the genesis of ventricular fibrillation.