absence of systole; failure of the ventricles of the heart to contract (usually caused by ventricular fibrillation) with consequent absence of the heart beat leading to oxygen lack and eventually to death
Should myocardial ischemia continue too long, myocyte death occurs, and electrical shock after this will only result in pulseless electrical activity or asystole. 如果心肌缺血时间过长，心肌细胞死亡，此时的电除颤只会产生无脉性电活动或心搏停止。
