Introduction
Catheter ablation for the treatment of atrial fibrillation (AF) has emerged as a safe1 and superior strategy compared to antiarrhythmic drug therapy in reducing AF recurrence2,3,4, improving quality of life5,6 , and reducing mortality and hospitalizations in patients with heart failure and reduced ejection fraction7,8. Expert consensus statements recommend that recurrence of AF be defined as any AF, atrial tachycardia (AT) or atrial flutter (AFL) of at least 30 seconds duration detected more than 3 months (i.e. the blanking period) following catheter ablation9. Success of the procedure varies depending on how success is defined, with significant differences in outcome definitions based on required AF duration as well as the monitoring strategy employed to detect treatment failure10,11,12,13. Furthermore, some authors have suggested that a reduction in AF burden may be a more objective endpoint rather than a binary outcome of recurrence as a measure of success14. This may be even more important given emerging data correlating AF duration and burden with risk of stroke15,16,17,18, a risk which may be attenuated in part by AF ablation19. The present exploratory analysis used a large de-identified electronic health record (EHR) dataset to assess how variations in defining AF recurrence and frequency and duration of monitoring influence an assessment of treatment success or failure.