动态分析急性心肌缺血模型中的非线性

Dynamical Analysis of the Nonlinearity in the Model of Acute Myocardial Ischemia

通过分析心脏电信号 ,许多学者已经发现正常的心脏和病态的心脏都有显著而突出的动力学特征。在此基础上 ,建立了 6只兔子急性心肌缺血实验模型 ,计算其不同时间段的 12导同步 ECG,作出关联维数 -时间 (D2- T)曲线和最大 L yapunov- T曲线 ,结合电生理和解剖学知识 ,研究了实验结果 ,证实了心肌缺血的存在会导致ECG的最大 L yapunov指数和关联维数的下降。 ECG的最大 L yapunov指数和关联维数分别反映了心脏系统的混沌性和复杂性 ,两者间没有明确的对应关系。关联维数更多受到了局部心脏系统状态的影响。

By analyzing the electrocardiosignals, many scholars have found remarkable and outstanding dynamic characteristics in both normal hearts and sick hearts. Based on those findings, a model of acute myocardial ischemia of six rabbits is designed by us and is presented here. The electrocardiogram (ECG) signals of different time series are calculated, and the figures of correlation dimensions-time and the maximum Lyapunov exponents-time are given. The results show that the existence of myocardial ischemia will bring the decline of the value of maximum Lyapunov exponents and correlation dimensions, after the figures being analyzed with electrophysiological and anatomical knowledge. The maximum Lyapunov exponents of ECG demonstrate the chaotic quality of the system and the correlation dimension of ECG demonstrates the complexity of the system, and there is no explicit relation between them. Correlation dimensions of ECG signals might be more influenced by partial heart system, compared with the maximum Lyapunov exponents of ECG signals.