动态心电图RR间期的Lyapunov指数谱

Lyapunov spectrum of RR\|intervals series in dynamic electrocardiogram

非线性动力学以复杂动力系统为研究对象，心脏是最为复杂的动力系统之一，心电图中ＲＲ 间期序列反应了心脏活动的重要信息，是诊断疾病的重要依据． Ｌｙａｐｕｎｏｖ 指数谱是处理复杂系统中非线性信息的重要方法，它可以反映复杂系统多项重要的特性．本文介绍了计算Ｌｙａｐｕｎｏｖ 指数谱的方法，利用ＭＩＴ－ＢＩＨ 心电数据库，计算了其中正常心律、起搏心律、室性失常心律和束支传导阻滞心律四组共２４ 例心电图数据中ＲＲ 间期序列的Ｌｙａｐｕｎｏｖ 指数谱，提出了收敛发散比的定义，并以此来衡量系统整体特性． 研究结果表明，正常心律和异常心律以及这三种异常心律之间，ＲＲ 间期的Ｌｙａｐｕｎｏｖ 指数谱和收敛发散比是有差异的，显示了这四种状态下心脏的不同动力学特征．为研究心脏的活动状态和进一步临床应用于心脏疾病的早期诊断提供帮助．

Nonlinear dynamics is used to study the characteristics of the complex nonlinear dynamic system. Heart is one of the most complex dynamic system. Indeed, RR\|intervals is important information in diagnose diseases of heart. Lyapunov Spectrum is a main method for processing nonlinear information. In this paper, Select 24 data files of ECG from MIT\|BIH database and divide these data into four groups. There are normal ECG, pacing ECG, ECG with ventricular arrhythmias, and ECG with bundle branch block. Queues of RR\|intervals extracted from these electrocardiograms are analyzed with Lyapunov spectrum. Define the Ratio of Convergency\|Divergency, which scales the integral kinetic characterizations of systems. The results showed that the Lyapunov spectrum and Ratio of Convergency\|Divergency are different between the normal ECG and other three abnormal ECG. This implies the different kinetic characterizations of the heart in the four states. Use the methods of Lyapunov spectrum to extract kinetic characteristics from ECG so as to research active states of heart and help doctors clinical application for early diagnostic diseases of heart in future.