The Study On HRV Clinic Analysis Technology

The Heart Rate Varibility (HRV) signal contains mass information, which concerns the cardiovascular nervous system and the body fluid. Much information about the status of autonomic nervous system can be obtained by means of examining patients' heart rate. HRV is considered as a convenient, non-invasive, quantitative and practical measure to detect and evaluate the function of heart's autonomic nervous system. It has become one of the hotspots in clinic and theory study.The task put a view to the study of HRV clinic analysis technology, which aims at research a series of fit arithmetic for clinic HRV analysis. The task roots in two aspects: one is the project of Chongqing Scientific Committee -Study on the relation between each frequence segment of HRV and autonomic nervous, and the copartner is the first affiliated hospital of Chongqing Medical University; another is the exploitation of autonomic nervous analyzer which cooperates with Chengdu Dikang medical digital equipment Ltd.The contents and outcomes of the study are mainly showed as follows:1) Preprocessing HRV signal. It contains designing filters for original ECG signal, detecting the key points of ECG, eliminating ectopic rhythms, even sampling the R-R intervals etc.2) Studying and comparing the two methods of computing power spectral density (PSD) that are periodogram and AR model. According to some special signal, the proper method will be chosen for HRV analysis in the frequency domain.3) Designing the contrastive medicine experiments between Atropine and Betaloc to discuss the inter-relation between HRV and autonomic nervous system, especially the relation between ULF and sympathetic nerve. The outcome shows that HF reflects the activity of vagus nerve, ULF reflects the function of sympathetic nerve better, and VFL and LF show the co-function of sympathetic nerve and vagus nerve.4) Computing and comparing HRV indexes among healthy person, the patients suffering from hypertension or coronary heart disease. It is to study hypertension and coronary heart disease's effect on the autonomic nervous' function, and offer the normal reference scope. The outcome shows that cardiovascular diseases can damage the function of autonomic nervous system, reduce the vagus activity, and relativelyenhance the sympathetic activity. It behaves in reducing each time-domain index, eliminating total power, dropping absolute HF power, increasing VLF/HF ratio.5) Discussing the nonlinear dynamic analysis methods for HRV. This paper chooses the Poincare Plot of R-R intervals, fractal correlative dimension and Lyapunov index to analyze the data of medicine experiments. The RR intervals plot can directly reflect whether the heart rhythm is normal. No matter what cause to damage the balance of autonomic nervous, the fractal correlative dimension will reduce. And when sympathetic nerve excitability acts dominantly, the Lyapunov index will eliminate.6) Choosing a fit time-frequency analysis method to study HRV. This paper selects Exponential Distribution(ED) that belongs to bi-linear distribution of Cohen class, and applies Running Windown Exponential Distribution (RWED) for programming. It can effectively reveal the characters of HRV signal both in time domain and frequency domain, and restrain the across- term.