Dissertation
Dissertation > Medicine, health > Internal Medicine > Heart, blood vessels ( circulatory ) disease > Heart disease > Arrhythmia > Atrial fibrillation and atrial flutter

The Modulation of Autonomic Nervous System In the Recurrence and Maintenance of Paroxysmal Atrial Fibrillation Based on HRV Analysis

Author WenFeng
Tutor ChenHang; PanJie
School Zhejiang University
Course Biophysical
Keywords paroxysmal atrial fibrillation heart rate variability HF LF detrending ectopic beat ectopic correction autonomic nervous system
CLC R541.75
Type PhD thesis
Year 2013
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Atrial fibrillation (AF) is the most common arrhythmia, and the research of the AF mechanisms will be beneficial to the clinical treatment. The mechanisms of autonomic nervous system of the breaking out and ending of paroxysmal atrial fibrillation (PAF) have been studied. We analyzed the pathological and physiological progresses from the fast recurrence to ending of PAF patients, and to the stage of transferring to the normal sinus rhythm, and calculated heart rate variability (HRV) indexes/parameters between different processes through the classification of PAF patients by the total duration of atrial fibrillation (TDAF). The significant index was detected from the different stages of PAF, to research the mechanisms of PAF with the modulation of autonomic nerve system (ANS) expressed by HRV indexes, to know the principle of PAF onset for clinical treatment.Methods and results:1, HRV analysis is the effective technique to estimate the heart electric signal, which is able to calculate the parameters of PAF by the three methods of time domain analysis, frequency domain analysis and nonlinear analysis. However, there are two problems existing on HRV technique. One is the influence of direct current (DC/trend) component and noise, while the other is ectopic beat that disturbing the sinus node pulse on ventricular response. They might have fatal confusion on the frequency and time domain processing. An advanced detrending method and an adjust ectopy technique were introduced in our work. The sinus rhythm on the ectopic beats was restored efficiently after these methods. The preprocessing of HRV analysis performed better with total error rate no more than1percent by the simulated signals. The error rate was on the acceptable degree for the reliable evaluation on PAF.2, The Holter data of95PAF patients were selected. HRV parameters were calculated during the segments with duration of5minutes just before, just after and1-hour after PAF episodes. The relationship of HRV parameters and TDAF was researched. The low frequency (LF) component and TDAF had significantly negative correlations during the three stages of PAF patients, and high frequency (HF) component and TDAF had significantly negative correlations during cardioversion time. The LF and HF were199±41and247±50(ms2) during the segment1-hour after PAF in the groups of TDAF<120min, whereas LF and HF were90±14and107±27in TDAF120-450,101±27和94±27in TDAF>450min.3, In the subjects of TDAF<120min, LF reflecting sympathetic modulation and HF reflecting vagal modulation had been increasing until10minutes before PAF onset, followed by a decrease immediately before PAF, significantly. Both of them decreased after PAF. In the subjects of TDAF>120min, LF and HF increased before and after PAF with fluctuations. The HF increased sharply before PAF onset in the patients with radiofrequency ablation.Conclusion:It indicates the maintenances of PAF are related to the poor modulation of the autonomic tone especially the sympathetic tone, whereas the onset and cardioversion of PAF are related to the enhanced modulation of vagal tone. The mechanisms of the ANS modulation before and after PAF are different between the patients with different TDAF. It is useful to realize the mechanisms of PAF and is auxiliary the treatment of AF patients.

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