Characteristic parameters from a human of electromagnetic signals heart system

The electromagnetic field of a human heart system is a bioelectromagnetic field. Electrocardiography （ECG） and magnetocardiography （MCG） are both carriers of electromagnetic information about the cardiac system, and they are nonstationary signals. In this study, ECG and MCG data from healthy subjects are acquired; the MCG data are captured using a high-Tc radio frequency superconducting quantum interference device （HTc rf SQUIDs） and the QRS complexes in these data are analysed by the evolutionary spectrum analysis method. The results show that the quality factor Q and the central frequency fz of the QRS complex evolutionary spectrum are the characteristic parameters （CHPs） of ECG and MCG in the time-frequency domain. The confidence intervals of the mean values of the CHPs are estimated by the Student t distribution method in mathematical statistics. We believe that there are threshold ranges of the mean values of Q and fz for healthy subjects. We have postulated the following criterion： if the mean values of CHPs are in the proper ranges, the cardiac system is in a normal condition and it possesses the capability of homeostasis. In contrast, if the mean values of the CHPs do not lie in the proper ranges, the homeostasis of the cardiac system is lacking and some cardiac disease may follow. The results and procedure of MCG CHPs in the study afford a technological route for the application of HTc rf SQUIDs in cardiology.     

Characteristic parameters of electromagnetic signals from a human heart system

The electromagnetic field of a human heart system is a bioelectromagnetic field. Electrocardiography (ECG) and magnetocardiography (MCG) are both carriers of electromagnetic information about the cardiac system,and they are nonstationary signals. In this study,ECG and MCG data from healthy subjects are acquired; the MCG data are captured using a high-T c radio frequency superconducting quantum interference device (HTc rf SQUIDs) and the QRS complexes in these data are analysed by the evolutionary spectrum analysis method. The results show that the quality factor Q and the central frequency f z of the QRS complex evolutionary spectrum are the characteristic parameters (CHPs) of ECG and MCG in the time-frequency domain. The confidence intervals of the mean values of the CHPs are estimated by the Student t distribution method in mathematical statistics. We believe that there are threshold ranges of the mean values of Q and f z for healthy subjects. We have postulated the following criterion: if the mean values of CHPs are in the proper ranges,the cardiac system is in a normal condition and it possesses the capability of homeostasis. In contrast,if the mean values of the CHPs do not lie in the proper ranges,the homeostasis of the cardiac system is lacking and some cardiac disease may follow. The results and procedure of MCG CHPs in the study afford a technological route for the application of HTc rf SQUIDs in cardiology.     

一种识别混沌时间序列动力学异同性的方法

定义了两个新的统计量，分别记为Q和R，Q称为动力学自相关因子指数，R称为动力学互相关 因子指数.用Q和R对不同时间序列的动力学“距离”或同一时间序列中不同区段（窗口）的 动力学“距离”进行估算，可以鉴别这些时间序列的动力学属性或它们内在的动力学结构层 次以及复杂性.一些典型实例检验表明，这种方法是有效的. 关键词： 混沌时间序列 动力学自相关因子指数 动力学互相关因子指数