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

Heart state information and neural control expounded by parameters is useful for early diagnosis of 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. A pathological notch on the QRS complex of an electrocardiogram (ECG) is defined as a local parameter, which is one of high-frequency components (HFC), and a Poincare dispersed-dot plot (PDDP) is defined as a nonlinear global one. Pathological notching information on the QRS complex is related to myocardial injuries. We have been working on man-made myocardial infarction models to simulate cardiac abnormalities. We found that both myocardial injury methods could produce a good idiosyncratic relationship between the injury area model and man-made pathological condition. A large number of repetitive experiments of the 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 the heart nonlinear state and rate variability and has thresholds about 26000 ms² area and 420 ms long axis for human beings and 600 ms² area and 85 ms long axis for dogs. Both parameters have showed that they have sensitive and early response of the heart state for pathological variation and also have dynamic characteristics.