交感神经调节失衡与缺血性心律失常关系的研究

为探讨急性心肌缺血后 ,交感神经对心室肌不同部位复极时程的调节及其与缺血性心律失常的关系 ,制备兔急性心肌缺血模型 ,分离、结扎并剪断双侧颈迷走、心交感神经 ,电刺激心交感神经远端。心室复极时程以心外膜电图 (EPG)的QT间期及采用玻璃微电极技术记录的动作电位时程 (APD90 、APD50 )表示。结果 :交感神经刺激使正常心室肌不同部位的QT间期、APD90 、APD50 均有明显缩短 (P <0 .0 5 ) ;不同部位心肌复极时程对交感神经刺激的反应性没有明显区别。急性心肌缺血后 ,交感神经刺激使缺血区QT间期、APD90 明显缩短 ,而非缺血区则无明显变化 ;非缺血区的QT间期、APD90 对交感神经刺激的反应性较缺血区明显减小 (P <0 .0 5 )。心肌缺血后心室易损期明显延长 ,交感神经刺激后更为延长 (P <0 .0 5 )。结论 :急性心肌缺血后 ,交感神经对非缺血区心室复极的调节作用减弱 ,交感神经兴奋导致心肌复极的不同步性更进一步增加 ,心室易损性增加 ,引起缺血性心律失常。

Relationship Between Sympathetic Nerves Regulation on Ventricular RepolarizationHeterogeneity and Ischemic Arrhythmia

To investigate the effect of sympathetic nerve stimulation (SNS) on ventricular repolarization period (VRP) in different zone and influence of changed VRP on ischemic arrhythmia.Methods:To make acute myocardial ischemia model of rabbit.To dissociate,ligate and cut bilateral cervical vagi and cardio sympathetic nerves (CSN).To stimulate peripherical end of CSN.QT interval in epicardiogram,action potential duration (APD 90 and APD 50 ) recorded by glass microelectrode technique as VRP,and responses of VRP to SNS were measured in different zone with and without LVB occlusion.VVP was tested with and without SNS and LVB occlusion.Results:VRP decreased with SNS ( P< 0.05) and responses of VRP to SNS was synchronous in different zone of rabbit.QT interval and APD 90 shortened in ischemic zone ( P <0.05) while didn't change in non ischemic zone with SNS;Responses of QT interval and APD 90 to SNS reduced significantly in non ischemic zone.Conclusion:The responses of VRP induced by SNS is different in ischemic and non ischemic zone which may increase the heterogeneity of VRP and vulnerability of ventricular myocardium and lead to ischemic arrhythmias.