Association of Atrial Fibrillation Episode Duration With Arrhythmia Recurrence Following Ablation: A Secondary Analysis of a Randomized Clinical Trial

Abstract

Importance: Contemporary guidelines recommend that atrial fibrillation (AF) be classified based on episode duration, with these categories forming the basis of therapeutic recommendations. While pragmatic, these classifications are not based on pathophysiologic processes and may not reflect clinical outcomes.

Objective: To evaluate the association of baseline AF episode duration with post-AF ablation arrhythmia outcomes.

Design, setting, and participants: The current study is a secondary analysis of a prospective, parallel-group, multicenter, single-masked randomized clinical trial (the Cryoballoon vs Irrigated Radiofrequency Catheter Ablation: Double Short vs Standard Exposure Duration [CIRCA-DOSE] study), which took place at 8 Canadian centers. Between September 2014 and July 2017, 346 patients older than 18 years with symptomatic AF referred for first catheter ablation were enrolled. All patients received an implantable cardiac monitor at least 30 days before ablation. Data analysis was performed in September 2019.

Exposure: Before ablation, patients were classified based on their longest AF episode. Ablation consisted of circumferential pulmonary vein isolation using standard techniques.

Main outcomes and measures: Time to first recurrence of symptomatic or asymptomatic atrial tachyarrhythmia (AF, atrial flutter, or atrial tachycardia) following ablation and AF burden (percentage of time in AF) on preablation and postablation continuous rhythm monitoring.

Results: The study included 346 patients (mean [SD] age, 59 [10] years; 231 [67.7%] men). Overall, 263 patients (76.0%) had AF episode duration of less than 24 hours; 25 (7.2%), 24 to 48 hours; 40 (11.7%), 2 to 7 days; and 18 (5.2%), more than 7 days. Documented recurrence of any atrial tachyarrhythmia following ablation was significantly lower in patients with baseline AF episode duration of less than 24 continuous hours compared with those with longer AF episodes (24 hours vs 24-48 hours: hazard ratio [HR], 0.41; 95% CI, 0.21-0.80; P = .009; 24 hours vs 2-7 days: HR, 0.25; 95% CI, 0.14-0.45; P < .001; 24 hours vs >7 days: HR, 0.23; 95% CI, 0.09-0.55; P < .001). Patients with preablation AF episodes limited to less than 24 continuous hours had a significantly lower median (interquartile range) postablation AF burden (0% [0%-0.1%]) compared with those with AF preablation episodes lasting 2-7 days (0.1% [0%-1.0%]; P = .003) and those with AF preablation episodes lasting more than 7 days (1.0% [0%-5.4%]; P = .008). There was no significant difference in arrhythmia recurrence or AF burden between the 3 groups with a baseline AF episode duration of longer than 24 hours.

Conclusions and relevance: In this study, patients with AF episodes limited to less than 24 continuous hours had a significantly lower incidence of arrhythmia recurrence following AF ablation. This suggests that current guidelines for classification of AF may not reflect clinical outcomes.

Trial registration: ClinicalTrials.gov Identifier: NCT01913522.

Conflict of interest statement

Conflict of Interest Disclosures: Dr Andrade reported receiving grants and personal fees from Medtronic during the conduct of the study and receiving personal fees from Biosense outside the submitted work. Dr Deyell reported receiving grants from Biosense Webster and receiving personal fees from Medtronic outside the submitted work. Dr Verma reported receiving personal fees from Medtronic and Servier, receiving grants from Biosense Webster, and receiving grants and personal fees from Bayer outside the submitted work. Dr Macle reported receiving grants and personal fees from Biosense Webster and grants from Medtronic outside the submitted work. Dr Leong-Sit reported receiving personal fees from Medtronic, Biosense Webster, and Baylis outside the submitted work. Dr Badra Verdu reported receiving personal fees from Medtronic outside the submitted work. Dr Sapp reported receiving grants from Biosense Webster and Abbott, receiving personal fees from Medtronic and Abbott outside the submitted work, and holding patents to US20140163395A1 Computer-Aided Localization of Site of Origin of Cardiac Activation and to a needle ablation catheter with rights assigned to Partners Healthcare. No other disclosures were reported.

Figures

Figure 1.. Freedom From Atrial Fibrillation (AF), Atrial Flutter (AFL), and Atrial Tachycardia (AT) After a Single Ablation Procedure, Stratified by the Longest AF Episode Recorded on Preablation Monitoring

Figure 2.. Atrial Fibrillation Burden Before and After Ablation, Stratified by Longest Atrial Fibrillation Episode Duration Recorded on Preablation Monitoring

Atrial fibrillation burden defined as percentage of time in atrial fibrillation. The center line indicates the median; the bottom and the top of the box, the 25th and 75th percentiles, respectively, and the lower and upper whiskers, the 10th and 90th percentiles, respectively.