A Novel Individualized Strategy For Cryoballoon Catheter Ablation In Patients With Paroxysmal Atrial Fibrillation

Objective:The traditional cryoablation strategy is single for the people with paroxysmal atrial fibrillation,however,different patients require different frozen doses due to differences in pulmonary vein anatomy.The risk of excessive frozen dose can lead to increased complications.This study wants to explore an individualized cryoablation strategy to reduce the cryotherapy application time,total procedure time,and left atrial dwell time,without reducing the surgical success rate and improving the patient’s surgical experience.Content:In this study,we developed an individualized cryoablation strategy for patients with paroxysmal atrial fibrillation,compared with traditional cryoablation strategies,and discussed and evaluated its safety and effectiveness.Methods:The study enrolled 232 patients with paroxysmal atrial fibrillation who was used the second-generation cryoballoon ablation for the first time.Patients in the study group(n=117)were guided by a time-to-pulmonary vein isolation(TTI)or the achievement for the balloon temperature to reach-40℃(Time-40℃)to achieve the ablation.When the pulmonary vein potential was measurable,the TTI was continuously monitored.If the TTI <60s,a TTI plus 60 s freeze time was applied for the first freezing,and then 120-s cryoballoon applications was applied for the bonus freeze per vein.If the TTI was between 60 and 90 s,a TTI plus 90 s freeze time was applied for the first freezing,and then 120-s cryoballoon applications was applied for the bonus freeze per vein.If the pulmonary vein potential was undetectable,patients were guided by the achievement for the balloon temperature to reach-40℃(Time-40℃),the first freezing time was performed at 120 s or 180 s respectively,and then 120-s cryoballoon applications was applied for the bonus freeze per vein.Patients in the control group(n=115)underwent a conventional strategy of 180-s cryoballoon applications per vein with a bonus freeze.Results:A total of 928 pulmonary veins were treated with 2101 cryotherapy applications.The mean number of applications per patient was 9.1 ± 0.8,with no difference between the groups(the study group,9.0 ± 0.8 versus.the control group,9.1 ± 0.7;P = 0.343).The study group required significantly less cryotherapy application time(1072.8 ± 136.7s versus.1638.8 ± 129.2s;P <0.001),procedure time(84.0 ± 11.9min versus.96.5 ± 16.0min;P <0.001),and the left atrial dwell time(68.0 ± 9.4min versus.81.4 ± 15.5min;P <0.001)than the control group.In addition,spontaneous recovery of pulmonary vein potential was observed in 43 pulmonary veins.The probability of pulmonary vein-left atrium reconnection was significantly different between the two groups[ respectively: the study group: 8(1.7%)versus.the control group 35(7.6%);P <0.001].After 12 months of follow-up,there was no difference in the incidence of tachyarrhythmia(atrial flutter,atrial tachycardia,or atrial fibrillation)[the study group: 25(21.4%)versus.the control group: 29(25.2%);P = 0.488].This study found that ablation of the right lower pulmonary vein(RIPV)sometimes is complicated.Beyond that,Hypertension is an independent predictor for the postoperative recurrence about cryoablation based on balloon temperature or pulmonary vein isolation time.Conclusion:Compared with traditional cryoablation methods,the individualized strategy of pulmonary vein isolation ablation guided by two cryotherapy parameters,balloon temperature or pulmonary vein isolation time,can significantly reduce the cryotherapy application time,total procedure time,and left atrial dwell time.Both of them have similar operating success rates,and 1-year follow-up outcomes were secure and effective.