The Response Of Ibutilide During The Radiofrequency Ablation Of Non-paroxysmal Atrial Fibrillation And The Relationship Of Arrhythmia Outcome

BackgroundCatheter ablation for atrial fibrillation(AF)has emerged as an important treatment strategy for symptom improvement and rate or rhythm control and the guideline recommendation levels are gradually increasing.Circumferential pulmonary vein isolation(CPVI)is more than ever the cornerstone of atrial fibrillation ablation strategies.However,the success rate of termination of atrial fibrillation and conversion to sinus rhythm by simple circumferential pulmonary vein isolation in nonparoxysmal atrial fibrillation is less than 20%,and the recurrence rate at long-term follow-up is high.Ibutilide is commonly used for termination of atrial fibrillation as an adjunct to ablation.We aimed to assess the relationship between the cardiac rhythm response to ibutilide infusion after pulmonary vein isolation and the recurrence of long-term atrial arrthymias.MethodsA total of one hundred and ninety-two patients with symptomatic,nonparoxysmal,non-valvular atrial fibrillation and endergoing firsrt catheter ablation were enrolled from January 2021 to December 2021.After circumferential pulmonary vein isolation,1 mg ibutilide was administered intravenously over 10 min in patients who did not terminate AF and were observed for 4 h for adverse effects.The groups were divided into two groups according to whether the sinus rhythm was successfully converted after drug administration(n=123)and the group with no conversion of ibutilide(n=69).The primary endpoint was any documented recurrence of atrial arrhythmia lasting more than 30 seconds after the initial catheter ablation.ResultsThe mean age of the cohort was 63 ± 9.46 years,61.5%were male,and the median duration of atrial fibrillation was 24 months.The proportion of patients who terminated conversion to sinus rhythm directly or by transcatheter conversion to atrial flutter/atrial tachycardia after ibutilide infusion was 64.0%.Larger left atrial diameter(Hazard ratio 1.017,95%confidence interval 0.807 to 1.128,P=0.033),older age(Hazard ratio 1.014,95%confidence interval 0.973-1.1345,P=0.026))and longer duration of atrial fibrillation(Hazard ratio 1.003,95%confidence interval 1.010 to 1.007,P=0.048)were associated with failed to termination of atrial fibrillation.At a median follow-up of 376 days(interquartile range:356 to 451)after initial catheter ablation,there were more atrial arrhythmia recurrences(log-rank,P=0.011)in the ibutilide-unresponsive group(n=69)than in the ibutilide-responsive group(n=123),and multifactorial Cox regression analysis showed that ibutilide-nonresponders were significantly associated with atrial arrhythmia recurrences(hazard ratio 1.994,95%confidence interval 1.117 to 3561,P=0.020).ConclusionIn non-paroxysmal atrial fibrillation patients after circumferential pulmonary vein isolation,response to ibutilide associated with recurrence of atrial arrhythmias,which may contribute to risk stratification of atrial fibrillation recurrence and individualized atrial fibrillation management.