Study Of Circumferential Pulmonary Vein Isolation Combined With Substrate Modification During Sinus Rhythm In The Treatment Of The Elderly With Paroxysmal Atrial Fibrillation

Background : Atrial fibrillation(AF)is the most common arrhythmia in clinical practice.It refers to the disorder of atrial electrical activity,which leads to atrial mechanical dysfunction.Age is an important risk factor for AF,and it is related to the increase of AF burden,which shows a sharp upward trend after 65 years old.Researches have shown that catheter ablation is more effective than antiarrhythmic drugs(AADs).Data also shown that catheter ablation is equally beneficial for older patients with symptomatic AF compared with younger patients.However,in patients with paroxysmal atrial fibrillation(PAF),the circumferential pulmonary vein isolation(CPVI)strategy has a limited success rate for a single procedure.Over time,the risk of recurrence gradually increases.More and more evidences show that left atrial fibrosis is closely related to the occurrence and maintenance of AF.Strategies focused left atrial(LA)substrate may improve the prognosis of these patients.Objective:We performed a high-density mapping(HDP)in LA after CPVI and then did substrate modification accordingly.We evaluate the effect and safety of CPVI combined with LA substrate modification during sinus rhythm compared with CPVI only in the treatment of the elderly patients with PAF.Methods:Two hundred and twenty elderly(age ≥65 years)patients with PAF were enrolled from January 2018 to February 2020,and randomly divided into study group(n=108)and control group(n=112).Through the 3-dimensional mapping system,multiple electrodes mapping catheter was used to reconstruct the imaging 3D model of the left atrium.After CPVI was finished,left atrial HDP was performed under sinus rhythm by the three-dimensional mapping system.The bipolar voltage 0.1-0.5m V was defined as the low-voltage area(LVA),and voltage < 0.1m V as the scar area.In the study group,LA-LVAs were ablated individually.While in the control group,LA-LVA were labeled only.Total area of left atrium,LA-LVA area,ratio of LVA to total area of left atrium,operation time,X-ray fluoroscopy time,X-ray exposure and ablation time were analyzed of the 2 groups patients with LVA.Results:After CPVI was finished in all patients,LA-LVA or scar area was detected in25 patients in the study group(25/108),and 28 patients in the control group(28/112).Left atrial LVA or scar area was detected in 25 of 108 patients in the study group and 28 of 112 patients in the control group.Compared with the control group,the ablation time(148.36 ± 7.21 min vs.132.07 ± 9.45 min,P < 0.05)and the total procedure time(67.28± 4.18 min vs.54.64 ± 4.97 min,P < 0.05)were longer in the study group.The X-ray exposure(54.28 ± 4.35 m Gy vs.53.92 ± 3.09 m Gy,P=0.739)and X-ray fluoroscopic time(9.20 ± 1.25 min vs.8.89 ± 1.07 min,P = 0.341)were not different significantly between the 2 groups.There was 1 patient with subcutaneous hematoma at the left subclavian vein puncture site in the study group(25/108)while 1 patient with minor pericardial effusion,and 1 patient with pseudoaneurysm at the right femoral vein puncture site in the control group(28/112),(1/25 vs.2/28,P =0.621).After a 1-year follow-up,the maintenance rate of sinus rhythm was higher in the study group with LALVA substrate modification than the control group without LA-LVA substrate modification(88% vs.60.7%,P=0.025).Conclusion: LA-LVA may be one of the factors for recurrence of AF after catheter ablation.The LA-LVA substrate modification after CPVI could improve the success rate of PAF ablation.Compared with the control group,the ablation time and total operation time were increased,while there were no more X-ray exposure,X-ray fluoroscopy time and complications in LA substrate modification group.