Background: The LB ablation system was developed to provide a new and unique visually based endoscopic technology for pulmonary vein isolation (PVI) The 2nd-generation laser balloon (LB2) offers optimized features for improved tissue contact and visibility. Long term follow-up data on clinical outcome of this system is still limited, especially in patients with persistent AF.

Objective: Evaluation of safety and long-term efficacy of PVI using the LB2 in patients with persistent AF as part of a single center non-randomized prospective study, the MERLIN registry.

Methods and Results: A total of 40 consecutive patients with symptomatic persistent AF were enrolled in our registry. All patients underwent PVI, using the LB2 ablation system. Five patients had a left common pulmonary vein (LCPV) and two patients had a right middle pulmonary vein (RMPV). A total of 156 of 157 (99.4 %) pulmonary veins (PVs) were successfully isolated by the LB2. Incomplete PVI occurred in one patient, due to emergent pericardial drainage before isolation of the last PV. Periprocedural complications occurred in a total of 4 out of 40 patients (10 %): a pericardial tamponade requiring pericardiocentesis; groin hematoma, one retroperitoneal hematoma requiring blood transfusion (no surgical intervention) and one with a partial phrenic nerve palsy.

The median follow-up period of our study was 12.8 months (interquartile range: 10.3; 17.8 months). A total of 31/40 (78 %) patients showed no recurrence free survival of atrial arrhythmia, including a 90-days long blanking period. Six out of 9 (66.7 %) patients with recurrent atrial arrhythmia underwent repeat ablations procedures. In 5 of 6 (83.3 %) patients undergoing repeat ablations presented with incomplete isolation of the pulmonary veins.

Conclusion: PVI with the LB2 in a patient population with persistent AF showed comparable short- and long-term results regarding safety and freedom of arrhythmia.