Significance of early recurrence of atrial fibrillation after catheter ablation: a nationwide Danish cohort study

Background Recurrence of atrial tachyarrhythmias after ablation of atrial fibrillation (AF) is common, although consensus guidelines advise against immediate re-ablation of “early recurrences” (occurring ≤ 90 days after ablation). However, recent studies show early recurrence is associated with “late recurrence” (occurring > 90 days) and question the duration of this “blanking period.” We investigated incidence and timing of early recurrence in relation to late recurrence in a large nationwide cohort. Methods From Danish nationwide registers, we included all patients aged 18 and older who underwent first-time ablation for AF between January 2005 and April 2017 and followed them for up to 2 years. Results Of the total 7339 patients included (72% male; median age 62 years), 2801 (38%) experienced early recurrence. The odds of late recurrence were 2.34 times higher (95% confidence interval, 2.09–2.63; P