交感神经对急性心肌梗塞后QT间期离散度的影响

目的本研究采用动物实验方法,旨在探讨交感神经对急性心肌梗塞(AMI)后QT间期离散度(QTd)变化的影响.方法观察去心交感神经组(A组)与保留心交感神经组(B组)新西兰兔在AMI前后的QTd,并行心内电生理检查诱发室性心动过速,对两组各指标进行比较,同时设置假手术组(C组)作为对照.结果C组在手术前后QTd比较无显著性差异(P＞0.05);A组去心交感神经前QTd与B组比较无显著性差异(P＞0.05);A组去心交感神经后QTd较前明显减小有显著性差异(P＜0.05).在AMI后B组QTd大于A组有非常显著性差异(P＜0.01);A组AMI前后QTd虽有变化,但无显著性差异(P＞0.05);而B组AMI后QTd大于AMI前有非常显著性差异(P＜0.001);B组室性心动过速诱发率高于A组有显著性差异(P＜0.05).结论在AMI的新西兰兔模型中,B组QTd显著大于A组,且更易诱发室性心动过速.提示交感神经活性增强在AMI后QTd变化及室性心律失常发生中起重要作用.

The Influence of Cardiac Sympathetic Nerve on QT Dispersion in Acute MyocardialInfarction

Objective: To study the sympathetic influence on QT dispersion after acute myocardial infaretion (AMI) in experimental rabbits. Methods:QTd of group A (rabbits without cardiac sympathetic nerve) and group B (rabbits with retained cardiac sympathetic nerve) were measured before and after AMI, and electrophysiologic examination was made to induce ventricular tachycardia(VT). The gained indexes of the two groups were analyzed and compared with each other. Group C (shame operation) was served as control. Results:QTd of group C had no significant changes before and after operation p>0. 05. Before cardiac sympathetic nerve was excised,QTd of group A was well-matched with that of group B p>0. 05. After cardiac sympathetic nerve was excised,QTd of group A was significantly smaller than before p<0. 05. QTd of group A was significantly smaller than that of group B after AMI p<0. 01. In group A,QTd after AMI was greater than before, but the difference was not significant p> 0. 05 ; but in group B, QTd after AMI was significantly greater than before p< 0. 001. In addition , the induced VT rate in group B was significantly higher than in group A (58. 33% vs. 8. 33%,p<0. 05). Conclusion: In AMI models of rabbits, QTd in group with retained cardiac sympathetic nerve was significantly greater than QTd in group with excised cardiac sympathetic nerve. Ventricular tachycardias were more easily induced in the former group. It was suggested that the increased sympathetic activity plays an important role in the changes of QT dispersion and in the occurrence of ventricular arrhythmia in AMI.