Early arrhythmia recurrence during the blanking period after pulsed-field ablation for atrial fibrillation.

BACKGROUND: Pulmonary vein isolation is a cornerstone in the treatment of atrial fibrillation, with procedural success traditionally assessed after a 3-month "blanking period" to account for early postablation arrhythmias. However, emerging evidence challenges this paradigm, particularly with nonthermal energy modalities such as pulsed-field ablation (PFA), which induce minimal inflammatory response. OBJECTIVE: The purpose of this study was to assess the prognostic relevance of early recurrence (ER) of atrial arrhythmia during the blanking period after PFA-based pulmonary vein isolation, with a focus on the timing of ER and its association with late recurrence (LR). METHODS: In this single-center study, 241 patients with atrial fibrillation underwent first-time PFA and were followed for ≥12 months. ER was defined as any atrial arrhythmia lasting >30 seconds within the first 3 months of ablation. The primary outcome was freedom from LR beyond the blanking period. RESULTS: ER occurred in 48 (20%) of patients, with 23 (48%) occurring within the first month and 25 (52%) during the second or third month of ablation. LR was significantly more frequent in patients with ER (P < .001), particularly when recurrence occurred after day 30. Multivariable Cox analysis identified ER during the second or third month (hazard ratio 6.1; 95% confidence interval 3.3-11.3) and ER during the first month (hazard ratio 3.6; 95% confidence interval 1.8-7.1) as the strongest independent predictors of LR. A subset of ERs resolved spontaneously. CONCLUSION: The timing of ER after PFA strongly predicts LR, supporting reconsideration of the 90-day blanking period. It may be appropriate to shorten the blanking period for PFA, but late ER warrants clinical attention. Larger studies should validate timing-based blanking strategies.