Impact of Early Atrial Tachyarrhythmia Within the Blanking Period on Late Recurrence After Pulsed Field Ablation of Atrial Fibrillation

BACKGROUND: Early atrial tachyarrhythmias (ERAT) occurring during the first 3 months after atrial fibrillation (AF) ablation were not traditionally considered a treatment failure, and this defined the blanking period after thermal energy ablations. More recent data suggest that the blanking period after pulsed field ablation (PFA) is shorter. We hypothesized that the traditional concept of "blanking period" does not apply to PFA for AF. OBJECTIVES: This study sought to evaluate whether ERAT during the 3 months after PFA for AF predicts late recurrence and whether or not the timing of ERAT affects late recurrences. METHODS: All consecutive patients undergoing PFA for AF at our institution (Feb 2024- March 2025) were enrolled in a prospective registry and followed to assess arrhythmia recurrences. ERAT was defined as atrial fibrillation or flutter lasting ≥30 seconds within 90 days. Late arrhythmia recurrences (LRAT) were defined as recurrences after 90 days. RESULTS: Among 1,608 patients followed for 1 year, 334 (20.8%) experienced ERAT and were more likely to experience LRAT than those patients without ERAT (68.4% vs 20.3%, P < 0.001). In multivariable Cox analyses, ERAT was independently associated with LRAT (HR: 4.89; 95% CI: 4.04-5.93; P < 0.001). The risk of LRAT was consistently elevated using 30-day and 60-day ERAT timing cutoffs: ERAT ≤30 vs 31-90 days (LRAT = 70.4% vs 65.5%; P = 0.41; adjusted HR: 5.40 vs 4.34 respectively compared with no ERAT) and ERAT ≤60 vs 61-90 days (LRAT = 68.6% vs 67.1%; P = 0.88; adjusted HR: 4.91 vs 4.83 respectively) compared with no ERAT. In secondary analyses, LRAT rates were similar in ERAT patients with or without cardioversion (73% vs 66.7%, P = 0.29). Interaction testing showed no significant differences in these HRs across ERAT-timing or cardioversion subgroups (all P > 0.05). Moreover, ERAT was associated with a higher need for cardioversion (25.1% vs 7.2%, P < 0.001; HR: 1.49; 95% CI: 1.10-2.02; P = 0.008) and late arrhythmia recurrences compared with patients without ERAT. CONCLUSIONS: After PFA for AF, atrial tachyarrhythmias at any time within the first 3 months, regardless of timing or need for cardioversion, strongly predict late recurrence and warrant increased monitoring intensity in the early postablation period.