Electrophysiological Findings in Patients with Early Recurrence During Blanking Period Following Atrial Fibrillation Ablation.

Background: Atrial tachyarrhythmias (ATa) during the blanking period (BP) may predict late recurrences of arrhythmia. This study evaluates the outcomes of redo procedures during BP in patients with early recurrence after catheter ablation (CA) for atrial fibrillation (AF).

Methods: This retrospective study included patients undergoing redo procedures within 3 months of their initial CA due to severely symptomatic ATa episodes. Baseline data, medications, and procedural details of initial and redo CAs were analyzed from medical records.

Results: Among 64 patients, 37 underwent cryoballoon (CB) and 27 underwent radiofrequency (RF) ablation. In the CB group, additional low-voltage areas beyond pulmonary veins, cavo tricuspid isthmus (CTI)-dependent flutter (27%), and left atrial reentrant tachycardia (30%) were common. Pulmonary vein reconnection was observed in 43%. In the RF group, left atrial macro/micro reentrant tachycardia (63%), CTI-dependent flutter (22%), and pulmonary vein reconnection (33%) were common causes of symptomatic ATas. After 12 months, 85.9% of patients (n = 55) were free from ATa following redo procedures.

Conclusion: Symptomatic ATas during BP often stem from substrates unrelated to the initial ablation, particularly in CB and pulmonary vein isolation-only RF groups. These findings suggest the need to reevaluate BP definitions, as select patients may benefit from early redo procedures to enhance long-term outcomes.