The Research Between Sympathetic Nerve And The Acute Atrial Fibrillation Induced By Rapid Pacing Dogs’ Right Atrium

Objective To study the relation of the sympathetic nerve and the acuteatrial fibrillation(AF) induced by rapid pacing right atrium of dogs, thereby toexplore the role of sympathetic nerve in breaking out and maintain of AF,andits possible mechanisms.Methods To investigate the role of the sympathetic in atrial fibrillationcanine model induced by rapid electrical pacing right atrium. AF canine modelswere set up. Twenty-five healthy adult mongrel dogs, mail and female informal,were randomly divided into five groups:①Sham-operation group(Sham group,n=5), were separated the left stellate ganglion through surgery, no stimulation orbroken;②The sympathetic nerve stimulation group(SNS group, n=5),the leftstellate ganglion was separated and recerived continuous electrical stimulation,make the foundation of sinus heart rate increased by30%and maintained at thislevel;③The sympathetic nerve divided group(SND group, n=5), the leftstellate ganglion was separated and cut off through surgery.④The isoprenalinegroup(ISO group, n=5), isoprenaline(0.5mg)+5%glucose injection(20ml)were intravenous injected slowly, make the foundation of sinus heart rateincreased by30%and maintained at this level.⑤The metoprolol group(MET group, n=5), metoprolol(1mg)+5%glucose injection(20ml) were intravenousinjected slowly, make the foundation of sinus heart rate increased by30%andmaintained at this level. PART1. A thoracotomy was used to fix thepacemaker electrode at the bottom of the right atrium, and electrode tip tocontact right auricular appendix vertically. AF model was set up by electricalpacing rapid atrium in short time. To test the atrium effective refractory period(AERP) and record the results of induced AF. Then we observe the influence ofdifferent measures of the data. PART2. Kill the animal by blocking circulationwhen electrophysiological index had been detected. Then we separate atrialtissue from the heart. We collect the right auricular tissue. Using WesternBlotting to detect the level of Cx40of canine auricular tissue in each group.Results PART1.1. The AERP of the SNS group and the ISO groupwere shortened than that of before intervention (P <0.05); The AERP of theSND group and the MET group were extended than that of beforeintervention(P <0.05).2. The SNS and ISO group success rate of atrialfibrillation induced increased significantly compared with that of beforeintervention (P <0.05); But the data of the SND and MET group had noobvious change (P>0.05). PART2. The expression level of Cx40of rightauricular appendix in the SYS, SND, ISO and MET group had neithersignificant difference compared with the Sham group (P>0.05). Theexpression level of the four group had neither significant difference with eachother (P>0.05).Conclusions1. Canine AERP may shorten by electrical stimulating thesympathetic nerve or by injecting isoprenaline to intervene the sympatheticnervous activity. However, the AERP can extend significantly by cutting off thesympathetic nerve or injecting metoprolol.2. Simple electrical stimulation of the sympathetic nerve or injecting isoprenaline can improve the frequency ofthe AF induced.3. There is no significant correlation between the frequency ofAF and the level of Cx40in canine acute AF model induced by rapid pacingright atrium.