Radial-linear Ablation In Peri-Pulmonary Vein Area For Therapy Of Acutely Induced Atrial Ifbrillation In Dogs

Objective: Atrial fibrillation (AF) is a common clinical arrhythmia, associated withhemodynamic changes and embolic events in patients with severe impact on quality of life,and lead to increased mortality and associated treatment costs.Now that the pathogenesis ofatrial fibrillation include focal excited and reciprocal excited to the theory, but they havenot fully integrated. Since Haissaguerre found that pulmonary vein focal ectopic currentcan lead to focal AF,it has been gradually formed a circumferential pulmonary veinablation(pulmonary vein isolation) as the cornerstone of ablation in the field ofradiofrequency ablation of atrial fibrillation.However, large clinical meta-analysis pointedout that a simple pulmonary vein isolation for atrial fibrillation ablation success rate was57%. There was reported, specially designed left atrial linear ablation without pulmonaryvein isolation, the success rate had been up to87%. At present, the pulmonary veinvestibule as substrate plays an important role in starting and maintenance of AF has beenwidely accepted.To this end, we designed a pulmonary vein vestibule radial linear ablationablation procedures.By animal experiments, to use atrial fibrillation dog model,induced byrapid electrical stimulation, we will discuss the safety and efficacy of the approach.Methods:1. Preparation of the model of atrial fibrillation:5-7years old adult dogs willbe anaesthetize by pentobarbital and electrophysiology catheter will be placed in rightatrial.AF will be induced by rapid atrial electrical stimulation. Then, they were randomlydivided into ablation group and control group.2. Ablation and sham-operated:PV of alldogs will be observed by venography after the puncture of atrial septum.Then, left atrialimage will be reconstruct by three-dimensional mapping system CARTO.Dogs of ablationgroup will undertake the pulmonary vein vestibular radial linear ablation while dogs ofcontrol group will not undertake this. Last, AF will be induced by the same procedure aspreoperative again in all dogs to evaluate the effect of ablation. And we will confirm thecontinuity of ablation lines by histological examination after ablation.Results:1. Preparation of the model of acute inducedatrial fibrillation:All dogs in theexperiment can induce atrial fibrillation by rapid atrial electrical stimulation,3cases ofpersistent artial fibrillation were induced in ablation group(12), and others were inducedparoxysmal atrial fibrillation, the incidence of AF was60.2%; the duration of AF was31.3 ±36.6s; the AF cycle length was132.2±7.4ms.The control group(10) were inducedparoxysmal atrial fibrillation all,the incidence of AF was63.0%; the duration of AF was34.7±27.6s; the AF cycle length was132.2±7.3ms.2. Ablation and sham-operation:Thedogs of ablation group undertook the pulmonary vein vestibular radial linear ablation bythe guide of CARTO.We can find that, compared with baseline, the incidence of AF was7.5%after ablation and fell87.6%(P<0.01);the duration of AF was2.7±6.2s after ablation,and fell91.4%,(P<0.01);.the AF cycle length was147.2±11.4ms after ablation andincreased11.3%(P<0.01).All dogs of control group can induce atrial fibrillation aftersham-operation(9case of paroxysmal,1case of persistent).The incidence of AF was64.84%;the duration of AF was43.9±17.1s;the AF cycle length was130.6±7.2ms,andcompared with before surgery were not significantly different. There was1case ofpericardial tamponade when puncturing atrial septumin in all dogs.3.Follow-up:In theperiod of4-24weeks(11.8±8.2weeks) after ablation,9dogs,undertook the ablation,wereinduced by rapid atrial electrical stimulation(by the same procedure as preoperative),andthe induced rate of paroxysmal AF was6.7%,with no significant difference afterablation(P>0.05).Additional, atrial fibrillation or atrial tachycardia can not be induced in3dogs whose follow-up time was greater than12weeks.Canine hearts of ablation groupwere examined through histological method and found continuous and complete ablationscars.Conclusion:1. The main finding of this study is that radial-linear ablation in peri-PVarea decreased the incidence of AF, and duration of AF in dogs. This novel strategy issimple and promising for treatment of paroxysmal AF by a PV antrum radial-linearablation.2. There was only1case of pericardial tamponade in all22dogs. Postoperative CTexamination found no pulmonary vein stenosis and left atrial thrombosis. So, the procedure isconsidered safe.