Posterior box isolation as an adjunctive ablation strategy during repeat ablation with the second-generation cryoballoon for recurrence of persistent atrial fibrillation: 1-year follow-up.

Background: The creation of a posterior box isolation of the left atrium (LAPWI) in addition to pulmonary vein isolation (PVI) with the second-generation cryoballoon (CB-A) seems to offer promising clinical outcome in patients affected by persistent atrial fibrillation (PersAF).
Aim: This work aims to study the clinical outcome of an ablation strategy based on the creation of a LAPWI during repeat procedures for recurrent AF after an index CB-A procedure for PersAF.
Methods and Results: A total of 33 patients having undergone a repeat procedure consisting in redo PVI plus LAPWI for recurrent PersAF with the CB-A after an index PVI ablation were retrospective included in our study. Electrical reconnection could be documented in 18 veins (13%). The LAPW was successfully isolated solely by CB-A ablation in 30 out of 33 (91%) patients; in the remaining 3 patients, isolation of the LAPW was completed by focal tip-irrigated RF ablation. The mean number of CB-A applications required for the superior portion of the LAPW and the inferior portion of the LAPW creation were 5.4 ± 0.9 and 4 ± 0.6, respectively. After a mean follow-up of 11.8 ± 3 months, 28 patients (85%) did not experience recurrence of any atrial arrhythmias during follow-up, without the need of further ablation or class I or III AADs.
Conclusion: Left posterior wall isolation with the CB-A is feasible and safe during repeat ablation procedures for recurrent PersAF. In our study, the 12-month freedom from any arrhythmia was 85% following this ablation strategy.