Heterogeneity in the definition of atrial fibrillation recurrence after catheter ablation - a systematic scoping review

Background/introduction Definitions of atrial fibrillation (AF) recurrence after catheter ablation (CA) vary widely, complicating interpretation and comparison of randomized trials. Purpose To identify and quantify the components that constitute recurrence definitions after CA. Methods We performed a systematic scoping review of MEDLINE, Embase, Web of Science (protocol registered at OSF). Eligible RCTs included pulmonary vein isolation in ≥1 arm, had ≥6-month follow-up, and reported both monitoring methods and recurrence endpoints. Data were extracted at the endpoint-instance level, allowing multiple endpoints per trial. Results We included 374 RCTs (334 main trials, 40 substudies; 16 categories), yielding 700 endpoint instances (Figure 1). Arrhythmia endpoints (n = 595) predominantly used episode-threshold definitions (n = 535) rather than burden-based definitions (n = 60), and were reported as primary endpoints in 49.9% of instances (28.6% as secondary endpoints, 21.5% not specified). Quality-of-life (QoL) endpoints were reported in 105 instances (74.3% as secondary endpoints) across 65 trials including substudies, and were concentrated within selected trial categories. In 21 trials, QoL was reported alongside burden; 6 tested an association between the two. The most frequently used questionnaires at the instance level were SF-36 (n = 31, 29.5%) and AFEQT (n = 15, 14.3%). Major sources of heterogeneity included blanking-period handling, monitoring method and intensity, antiarrhythmic drug policies (during blanking and follow-up), treatment of repeat ablation (during blanking and follow-up), episode cutoff, arrhythmia scope, and outcome construct (time-to-event vs binary) (Figure 2). Some components became more standardized over time. The adoption of a 3-month blanking period and the allowance to use or change antiarrhythmic drugs within this period both increased over the years. Conclusions Recurrence definitions after CA are multi-component and therefore prone to heterogeneity. By rendering the components of these definitions, this review offers a shared framework to investigate sources of heterogeneity and lays a foundation for endpoint harmonization, facilitating more consistent outcome reporting in future AF ablation RCTs and meta-analytic synthesis.Flow DiagramDefinition Components