Research On The Regulation Mechanism Of Vegetative Nervous System For Atrial Fibrillation Based Heart Rate Variability

Vegetative nervous system is the neural structures to regulate visceral function, it also be called the autonomic nervous system(ANS). because it contacts with central nervous system and smooth muscle and glands of viscera, and automatically adjusts visceral function, which is difficult to be controlled by individual consciousness. Recently, a large number of research indicates that abnormal activity of ANS will cause arrhythmias. AF, which is short for atrial fibrillation, is a widespread arrhythmia and be found in many kinds of cardiovascular diseases. A large number of experiments and studies show that the episode and development of AF are related to this imbalance of ANS. This paper aims at revealing the information and regulatory mechanisms of autonomic nervous system by using the parameters of HRV and computational methods.The research of the thesis contains two parts:Based on the parameters HRV and QT intervals, the first part aimed at studying the regulatory mechanism of ANS of AF. We focus on three kinds of ECG : sinus ECG from healthy individuals, normal ECG and AF ECG from patients with AF, which is to understand the regulatory mechanisms of ANS in AF patients. In our conclusion, AF will make sympathetic activity excited, however, when sympathetic-vagal balance is maintained, the abnormal neural activity will not unduly affect the ventricular repolarization; the instability of the ventricular repolarization is closely related to the change of abnormal sympathetic tone in patients; finally, this abnormal sympathetic tone change results in an imbalance of sympathetic-vagal nerve activity,which is closely linked to the episodes of AF.Based on the analysis in frequency-domain, the second part aims at the studying the regulatory mechanism of ANS to AF and ventricular tachycardia(VT). We analyze the ECG data of standard 12-lead from the AF patients or VT patients to dig out the regulatory information of ANS for different heart diseases, and deeply understand the pathogenesis of atrial fibrillation. In our conclusion, When AF occurs, the imbalance of the sympathetic-vagal nerve system is an important reason of changing the components of frequency domain; there is a significant difference in the regulation mechanism of ANS between AF and VT.