迷走神经刺激对老年大鼠缺血性室性心律失常的影响

目的：探讨急性心肌缺血时迷走神经刺激对老年大鼠缺血性室性心律失常的影响及其潜在的作用机制。方法：雄性SD大鼠80只，结扎大鼠冠状动脉前降支制备急性心肌缺血模型分为：（1）成年组：心肌缺血组（MI组，陀=15）、心肌缺血＋迷走神经刺激组（MI—Vs组，乃=15）和假手术组（sO组，n=10）；（2）老年组：心肌缺血组（MI组，儿=15）、心肌缺血＋迷走神经刺激组（MI．VS组，凡=15）和假手术组（S0组，n=10）。心电图监测各组室性心律失常的发生，并进行比较。结果：结扎冠状动脉30min内，老年MI组室速和室颤发生率较成年MI组显著增加（P〈0．05）；老年MI．VS组与老年MI组室速和室颤发生率无明显变化（P〉0．05），老年MI—VS组不可逆性室颤发生率较老年MI组明显减少（P〈0．05）。结论：老年大鼠缺血性室性心律失常发生率明显增加，而迷走神经刺激的抗缺血性室性心律失常的效应却明显减弱。

Effect of vagal nerve stimulation on ischemia-induced ventricular arrhythmias in aged rats

Objective: To investigate the effect of vagal nerve stimulation on ventricular arrhythmias during acute myocardial ischemia in aged rats.Methods: Male SD rats were randomly assigned into the following groups:(1) Adult group: Myocardial ischemia(MI) group(n=15): ligation of the anterior descending coronary;Myocardial ischemia + Vagal stimulation(MI-VS) group(n=15) and sham operation(SO) group(n=10): without coronary ligation.(2): Aged group: Myocardial ischemia(MI) group(n=15);Myocardial ischemia + Vagal stimulation(MI-VS) group(n=15) and sham operation(SO) group(n=10).Ventricular arrhythmias were monitored by an electrocardiogram.Results:The incidences of VT and VF of the MI group in aged rats increased significantly during the 30-minute ligation compared to those of the MI group in adult rats(P<0.05);there were no significantly differences in the incidences of VT and VF between the MI-VS group and the MI group in aged rats(P>0.05);however,the irreversible VF of the MI-VS group in aged rats decreased significantly compared to that of the MI group in aged rats(P<0.05).Conclusion:The present study showed that the incidence of ischemia-induced ventricular arrhythmias increased markedly in aged rats,and the anti-arrhythmic effect of vagal nerve stimulation decreased significantly in aged rats.