Study of the state variation and neural control parameters of the heart *

* Abstract-Heart state information and neural control expound by parameters is useful to early diagnose heart diseases. The purpose of this article was to investigate the efficiency of parameters that express heart state variation and neural control. We have studied three kinds of parameters: global, local and dynamic with different methods to extract heart concealed physiological and pathological information with animal models. Pathological notch on QRS complex of electrocardiogram (ECG) is defined as local parameter which is one of high-frequency components (HFCs) and poincare dispersed-dot plots (PDDP) is defined as nonlinear global one. Pathological notching information on the QRS complex is related with myocardial injuries. We have been working on man-made myocardial infarction models to simulate cardiac abnormalities. And we found that both myocardial injury methods could produce good idiosyncratic relationship between injury area model and man-made pathological condition. A large number of repetitive experiments of animal model indicated that the thresholds of pathological notching have about 84 uV amplitude and 3.8 ms width. The PDDP was a good parameter of heart nonlinear state and rate variability and has thresholds about 26000 ms area and 420 ms long axis for human being and 600 ms area and 85 ms long axis for dogs. Both parameters have showed that they sensitive and early response of heart state of pathological variation and also have dynamic characteristics.