Effect Of Canine Posterior Left Atrium Autonomic Nervous System On Electrophysiological Mechanism Of Atrial Fibrillation

Background: Atrial fibrillation(AF)is one of the most common cardiac arrhythmias at present.However,the mechanism of atrial fibrillation is not completely elucidated.Thus,exploring the new mechanism of atrial fibrillation is undoubtedly very important in the future.There is a very complicated relationship between autonomic nervous system and cardiac system.Recent studies have shown that the posterior left atrium(PLA)is the most abundant area of autonomic nervous fibers in the left atrium,and research have found that PLA is associated with the maintenance of atrial fibrillation.Therefore,it is necessary to study the electrophysiological mechanism of autonomic nervous system in atrial fibrillation and explore the new treatment strategy.Objective: The aim of this study was to investigate the electrophysiological mechanism of canine PLA autonomic nervous system in atrial fibrillation on the canine model.This research mainly includes four parts:(1)To explore the effect of PLA autonomic nervous system activation on the occurrence of atrial fibrillation by establishing a canine heart model.(2)To explore the effect of PLA autonomic nerve on the occurrence of atrial fibrillation by stimulating vagal nerve and blocking PLA autonomic nervous system.(3)To explore the electrophysiological mechanism of PLA autonomic nervous system on the occurrence of atrial fibrillation induced by rapid atrium pacing(RAP).(4)Under the guidance of the carto,investigate the effect of PLA autonomic nerve ablation on electrophysiological mechanism of atrial fibrillation induced by RAP.Methods:(1)8 Beagle dogs were operated on cardiac surgery and the PLA autonomic nerve were stimulated by high-frequency stimulation(HFS,S1-S2 train),then investigate the induction rate and duration time of AF under the HFS.(2)16 Beagle dogs were randomly divided into vagal stimulation group and control group.Measure the effective refractory period(ERP),ERP dispersion(ERP-COV),induction rate of AF,window of vulnerability(WOV)in the PLA,left atrial roof(LAR),pulmonary vein(PV),left atrial appendage(LAA)before and after PLA autonomous nervous system was blocked.(3)16 Beagle dogs were randomly divided into two groups: group 1 was given atropine after 6 hours of RAP.Group 2 was given atropine first and stimulated by 6 hours of RAP.Measure the ERP,ERP-COV,induction rate of AF,WOV at baseline,1h,2h,3h,4h,5h,6h after RAP and atropine was given respectively.(4)16 Beagle dogs were randomly divided into ablation group and control group.Measure the ERP,ERP-COV,induction rate of AF,WOV at baseline,1h,2h,3h,4h,5h,6h after RAP.Results:(1)AF can be induced by stimulating the PLA autonomic nerve and failed to be induced after PLA autonomic nervous system was blocked by drug.(2)Compared with the control group,ERP was significantly shortened.ERP-COV,induction rate of AF and WOV was significantly increased in the vagal nerve simulation group.The effects could be inhibited after PLA autonomic nervous system was blocked.(3)After 6 hours of RAP for left atrium,ERP was significantly shortened.the ERP-COV,induction rate of AF and WOV significantly increased in the dogs.The effects could be inhibited after PLA autonomic nervous system was blocked.(4)Compared with the control group,the left atrial ERP increased.the ERP-COV,induction rate of AF and WOV decreased significantly in the ablation group after RAP.Conclusions:(1)The activation of PLA autonomic nervous system is associated with the mechanism of occurance of atrial fibrillation.(2)The vagal nerve stimulation could have effect on the electrophysiology mechanism of the atrium,the activation of PLA autonomic nervous system is associated with the electrophysiological mechanism of the atrium.(3)ERP shortening,increase of ERP-COV,increase of AF incidence,increase of WOV and other electrical remodeling phenomenon induced by RAP could be inhibited after PLA autonomic nervous system was blocked by drug,PLA autonomic nervous system is associated with electrical remodeling mechanism induced by RAP.(4)The electrophysiological effects of RAP and incidence of atrial fibrillation could be reduced after ablation of the PLA autonomic nervous system.