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    Original Investigation
    Cardiology
    July 2, 2020

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

    Author Affiliations
    • 1Montreal Heart Institute, Department of Medicine, Université de Montréal, Montréal, Quebec, Canada
    • 2Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
    • 3Center for Cardiovascular Innovation, Vancouver, British Columbia, Canada
    • 4Southlake Regional Health Center, Newmarket, Ontario, Canada
    • 5Université Laval, Quebec City, Quebec, Canada
    • 6University of Western Ontario, London, Ontario, Canada
    • 7Royal Jubilee Hospital, Victoria, British Columbia, Canada
    • 8Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Quebec, Canada
    • 9Queen Elizabeth II Health Sciences Centre, Dalhousie University, Halifax, Nova Scotia, Canada
    JAMA Netw Open. 2020;3(7):e208748. doi:10.1001/jamanetworkopen.2020.8748
    Key Points español 中文 (chinese)

    Question  What is the association between preablation atrial fibrillation (AF) episode duration and arrhythmia recurrence outcomes following AF ablation?

    Findings  In this prespecified subanalysis of a randomized clinical trial of 346 patients with symptomatic AF undergoing catheter ablation, patients with AF episodes limited to less than 24 continuous hours had a significantly lower rate of recurrence following an ablation procedure. Arrhythmia recurrence and AF burden after ablation did not differ between patients with persistent AF (episodes lasting >7 days) and those with paroxysmal AF (episodes lasting 24 to 48 hours or 2 to 7 days).

    Meaning  The findings of this study suggest that the contemporary definition of paroxysmal AF does not reflect post-AF ablation arrhythmia outcomes.

    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

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