急性心肌梗死后快速刺激诱发心室颤动的"混沌机制"的研究

目的探讨急性心肌梗死后心室颤动(室颤)的发病机制,观察室颤过程中“混沌”的非线性动力学特征,为临床预防急性心肌梗死后室颤的发生提供理论依据。方法2003-06～2005-12对中国医科大学附属第二医院心内科制造的急性心肌梗死模型,快速起搏刺激犬的在体心肌并诱发室颤,用64导心外膜标测系统记录室颤过程中心肌的电生理学参数,观察激动周期的动态改变。结果急性心肌梗死时,诱发室颤的刺激间期明显提高;快速刺激诱发室颤的过程中,激动周期呈现倍周期分叉、准周期乃致混沌等非线性动力学特征,其Poincare作图为环状结构。结论心肌急性缺血导致室颤的阈值明显升高;室颤是由于系统呈现倍周期分叉、准周期乃致混沌而导致。

Research on mechanism of chaos during ventricular fibrillation induced by rapid pacing after acute myocardial infarction

Objective To investigate the mechanism of chaos during ventricular fibrillation(VF)after acute myocardial infarction(AMI)and observe the property of nonlinear dynamics of VF in order to provide clinical doctors with theory evidences to prevent VF after AMI.Methods From Jun.2003 to Dec.2005,we made the acute myocardial infacrtion model and induced VF of canine in vivo by using rapid pacing,and recorded the cardiac electrophysiological parameters by using 64-trains multi-polar epicardial-mapping electrocardiogram system to observe the change of the cycle length(CL)of ventricular arrhythmia in the Second Affiliated Hospital of China Medical Univercity.Results The pacing interval of VF in acute ischemia myocardium had been significantly increased; the cycle length(CL)showed the spatiotemporal complexity,such as period doubling bifurcation and quasiperiodicity and its Poincar'e plots formed a ring-like structure meaning nonlinear dynamics property during VF.Conclusion The liminal value of VF has been significantly increased during acute myocardial infarction.VF is induced by system come-into period doubling bifurcation,quasiperiodicity and chaos.