Effect of early cryoballoon ablation on atrial fibrillation recurrence - a nationwide register study
Authors: Hein R , Riis-Vestergaard L , Toennesen J , Zoerner C , Pallisgaard J L , Hansen M L 
Published: November 2023

Abstract

Introduction
Cryoballoon ablation seems a viable first-line therapy in atrial fibrillation (AF) patients and outperforms antiarrhythmic drugs (AAD) regarding sinus rhythm maintenance. Despite this, guidelines in general recommend AAD use before ablation for AF, delaying a potential ablation. Therefore, data regarding the impact of the timing of cryoballoon ablation on AF recurrence in large, unselected cohorts is highly warranted.

Purpose
To examine AF recurrence after AF cryoballoon ablation by time from AF diagnosis to AF ablation.

Methods
From nationwide registers, we included all AF patients above 18 years who underwent first-time cryoballoon ablation from January 2010 to December 2018. The AF patients were stratified by ablation timing: Early ablation (&lt; 1 year after AF diagnosis) and late ablation (≥1 year after AF diagnosis). The primary endpoint was recurrent AF, defined as a composite endpoint of AF hospitalization, claimed prescriptions of AAD, re-ablation or electrical cardioversions. The cumulative incidence of recurrent AF at 5-year follow-up after a blanking period of 90 days was estimated using the Aalen-Johansen estimator, taking the competing risk of death into account. The relative rates of recurrent AF were examined using cox models adjusted for sex, age, procedure-year, left atrial size, body mass index, AF-type (paroxysmal or persistent), hypertension, heart failure, ischemic heart disease, and chronic obstructive pulmonary disease.

Results
The study cohort consisted of 677 patients, 204 in the early ablation group and 473 in the late ablation group. Median age increased from 59 in the early ablation group to 65 in the late ablation group. In the early ablation group 71% had paroxysmal AF compared to 66% in the late ablation group. Use of amiodarone and Class 1C antiarrhythmic medication were higher in the late ablation group.
The 5-year cumulative incidence of recurrent AF was 41% and 51% in the early and late ablation groups. The Hazard ratio (HR) and 95% confidence interval (95% CI) were 1.44 and (CI 1.10-1.89) in the late ablation group compared to the early ablation group (Figure 1).
For paroxysmal AF the 5-year cumulative incidence of recurrent AF was 41% and 49% in the early and late ablation groups with a HR of 1.32 (CI 0.95-1.84) in the late ablation group compared to the early ablation group. For persistent AF the 5-year cumulative incidence of recurrent AF was 39% and 59% in the early and late ablation groups with a HR of 1.74 (CI 1.05-2.87) in the late ablation group compared to the early ablation group (Figure 2).

Conclusion
In this nationwide register study examining recurrent AF after cryoballoon ablation, we found lower recurrence rates when early ablation was performed. Based on this, early cryoballoon ablation could potentially provide considerable benefits and improve outcomes after ablation, indicating that cryoballoon ablation as first-line therapy might be ideal.Figure 1Figure 2