Early Versus Late Atrial Fibrillation Recurrence After Pulsed Field Ablation: Insights From the admIRE Trial.

Background and aims: Studies have shown correlations between early recurrence (ER) and late recurrence (LR) of atrial arrhythmia after ablation with thermal technologies. This admIRE trial (NCT05293639) subanalysis aims to analyze ER versus LR in patients with paroxysmal atrial fibrillation (PAF) undergoing pulsed field ablation (PFA).

Methods: Patients with symptomatic paroxysmal atrial fibrillation and ≥1 transtelephonic monitoring transmission during the blanking period were included (n=169). ER was defined as documented recurrence in the blanking period (days 1-90), and LR as recurrence in the evaluation period (days 91-365). Freedom from 12-month recurrence was estimated using Kaplan-Meier method. A Cox proportional-hazards regression model, with ER as the primary factor, and adjusted for age, sex, and body mass index, was used to estimate hazard ratios (HRs) and 95% CI.

Results: ER was observed in 20.1% (31/169) of patients (66.1±7.1 years, 35.5% female, 46.6±48.4-month PAF history). Time to first documented ER was 49 (37-61) days. Occurrence of LR was 16.7% (23/138) in patients without ER, 71.0% (22/31) in those with ER, and 87.0% (20/23) in patients whose ER onset occurred within the first 2 months. Twelve-month freedom from documented recurrence was significantly lower in patients with ER at 29.0% (95% CI, 13.1%-45.0%), versus 82.5% (95% CI, 75.9-89.1%) in those without ER (adjusted HR, 7.9; 95% CI, 4.1-15.1; P<0.001).

Conclusion: This admIRE subanalysis demonstrated that PAF patients who experience ER after PFA are at a substantially higher risk for LR. The optimal duration of the blanking period post PFA need further assessments.