Aims: It has been known that cryoballoon-based pulmonary vein isolation (PVI) is an efficacious and a safe therapeutic option to eliminate triggers of atrial fibrillation (AF). However, the effect of cryoablation on external modifiers of AF-like ganglionated plexi (GP) has never been investigated. In this study, we aimed to investigate whether vagal reactions probably due to GP modification during cryoablation, are associated with success rates during follow-up.
Methods and results: A total of 145 patients (age: 54.5 ± 10.1, 52.4% males and 80.7% paroxysmal AF) who were symptomatic despite treatment with ≥ 1 antiarrhythmic drug underwent PVI with cryoballoon. Occurrences of intraprocedural vagal reactions were recorded in all patients. Intraprocedural vagal reaction was observed in 59 patients (40.7%). Vagal reaction characterized by bradycardia and hypotension was more common in patients free of AF recurrence as was the requirement of atropine administration or temporary pacing (46.2 vs. 15.4%, P = 0.004 and 38.7 vs. 7.7%, P = 0.002, respectively). At a median 17 (4-27) months follow-up, AF recurrence was observed in 26 (17.9%) patients. Multivariate Cox regression analysis showed that non-paroxysmal AF, left atrial diameter, and early recurrence significantly increased AF recurrence; however, requirement of atropine administration or temporary pacing (hazard ratio: 0.064; 95% confidence interval: 0.008-0.48, P = 0.008) decreased AF recurrence.
Conclusion: Our findings indicate that vagal reactions during cryoablation, as a surrogate marker of cardiac ANS modification, decrease AF recurrence in a subgroup of patients with paroxysmal and persistent AF. This finding may be attributed to the concomitant ablation of GP during antral PVI.
Keywords: Atrial fibrillation; Cryoablation; Recurrence; Vagal reaction.