The Temporal Atrial Fibrillation Pattern during the Blanking Period after Atrial Fibrillation Ablation Is Associated with Later AF Recurrence

Objective: Atrial fibrillation (AF) ablation can introduce a period of transient electrical instability for an extended period after the procedure. Several investigators and consensus statements indicate that arrhythmias observed during the 3 month “blanking period” should not be taken into account for evaluation of procedural success. The aim of the present study was to evaluate if the quantity and temporal pattern of the arrhythmias during the blanking period can provide valuable insights regarding future AF recurrence and indirectly the success of the ablation.

Methods: Ninety-nine patients (73 male;age:68.0 ± 9.2years) with documented preoperative AF (paroxysmal:29; persistent:18; long-lasting persistent: 52, mean preoperative duration: 46 ± 53 months) underwent concomitant biatrial surgical ablation (Cox-Maze III:29), full set left atrium cryoablation (n = 22), high intensity focused ultrasound [HIFU] box lesion (n = 46) or right sided ablation (n = 2). Postoperative rhythm disclosure was provided via an implantable device. In all patients, the cardiac rhythm history was reconstructed. The quantity of AF recurrence (AF burden) and its temporal aggregation (AF density) during the blanking period was regressed on the AF burden developed in the remaining observation time.

Results: During the blanking period AF recurrence was observed in 56/99 patients, with a median AF burden of 0.004 (IQR: 0.001–0.019), occurring with a median AF density of 0.87 (IQR: 0.68–0.96). During the remaining observation period, some AF recurrence occurred in 89/99 patients albeit the AF burden of these patients during this period was negligible (median: 0.001, IQR: 0.0001–0.007). Both the AF burden (p < 0.0001) and AF density (p = 0.004) observed during the blanking period was significantly associated with later AF recurrence. This effect persisted after correcting for type of AF, type of ablation (energy source), and known preoperative AF duration. Higher AF burden occurring with low AF density during the blanking period may indicate prolonged electrical instability and is associated with higher AF recurrence during the remaining observation period.

Conclusion: The quantitative and temporal characteristics of AF recurrence during the blanking period can provide valuable insights on the severity of electrical instability and the amount of later AF recurrence, and may provide prognostic information on the success of the ablation procedure.