Frequency of recurrence following cardioversion of an initial atrial fibrillation episode

Abstract Background Direct current cardioversion (DCCV) is a common first-line therapy for newly diagnosed atrial fibrillation (AF). Although AF recurrence is common after DCCV, some patients do not develop AF again for decades. Characterization of the frequency and risk factors for AF recurrence after DCCV for an initial AF episode is needed to prioritize individuals for more intensive monitoring and therapies (e.g., anticoagulation, anti-arrhythmic drugs, catheter ablation). Purpose We aimed to evaluate the frequency and risk factors for AF recurrence following DCCV for a first-time AF episode. Methods Within a large, multi-institutional electronic health record-based cohort of primary care and ambulatory cardiology patients, we identified individuals undergoing DCCV for newly diagnosed AF between 2000-2019. DCCV for newly diagnosed AF was defined as a DCCV procedure occurring with a concomitant AF diagnosis between 30 days before to 7 days after (manual review of n=100 cases with positive predictive value 82%). We then quantified rates of AF recurrence and fit Cox proportional hazards models to identify clinical factors associated with AF recurrence. Candidate factors included age, race, and AF-related risk factors including hypertension, diabetes mellitus, coronary artery disease, myocardial infarction, heart failure, obesity, antihypertensive medication use, and current smoking. Results Of 569,873 patients, 1,293 underwent DCCV for a newly diagnosed AF episode (65.3±14.2 years, 41% female). Over median 4.7 years, 790 patients had AF recurrence, corresponding to an incidence rate of 28.4 per 100 person-years and a 5-year cumulative risk of 66.4% (95% confidence interval CI 63.2–69.2) (Figure A). In multivariable models, age (hazard ratio HR 1.14 per 5-year increase, 95% CI 1.1–1.17), White race (HR 2.08, 95% CI 1.61–2.69), and obesity (HR 1.19, 95% CI 1.01–1.4) were strongly associated with AF recurrence. Longitudinal AF recurrence was substantially stratified by age at first DCCV, with patients aged ≥75 years having 5-year recurrence of 83.7% (95% CI 79–88.1) (p0.001) (Figure B). Conclusion AF recurrence occurs within 2 years among most patients undergoing DCCV for a newly diagnosed AF episode. Recurrence is nearly universal among older individuals, who may benefit from more intensive monitoring and consideration of early medical or procedural rhythm control.