Abstract Funding Acknowledgements Type of funding sources: None. Background Visually guided laser balloon ablation (LBA) is a promising method for pulmonary vein (PV) isolation in the treatment of atrial fibrillation (AF). To reduce procedural times, the rapid mode feature (RM), which offers an automated continuous 360° lesion for pulmonary vein isolation, was implemented in the latest version of the laser balloon system. Purpose We evaluated the learning curve for LBA in the treatment of AF Method We enrolled the first 74 patients with paroxysmal or persistent AF treated with LBA in our centre between September 2020 and December 2021. Exclusion criteria were any contraindication for the procedure. 3 different time intervals were considered (time 1 T1, time 2 T2 and time 3 T3), which included the first 25 patients, the next 25 patients and the last 24 patients, respectively. We compared fluoroscopy and procedural time and the number of pulmonary veins isolated by RM >90% (>324°) among the three group were compared. Results There was no difference between the three intervals in terms of age (61.2 ±9.00 vs 63.9 ±11.4 vs 58.4 ±12.9; p=n.s.), sex (68% vs 64% vs 81%; p=n.s.) and clinical characteristics. The procedural time (see picture 1) was significantly reduced from T1 to T2 (199 ±51.8 in T1 vs 159 ±38.6 in T2; p< 0.01), while there was no variation between T2 and T3 (159 ±38.6 in T2 vs 153 ±51.9 in T3; p=n.s.). We detected a reduction in fluoroscopy time between T1 and T2 (38.8 ±15.2 in T1 vs 28.8 ±10.5 in T2; p<0.01) but not further reduction was observed between T2 and T3 (28.8 ±10.5 in T2 vs 30.5 ±16.7 in T3; p =n.s.). Considering the use of (RM) feature, there was a progressive increase in the number of PVs isolated by RM >90% over time (1.0 ±0.7 PVs in T1 vs 2.0 ±1.2 PVs in T2 vs 3.3 ±0.9 in T3: p <0.01). Five pinhole balloon ruptures were observed, three in the T1 group, two in the T3 group. Temporary phrenic nerve dysfunction occurred in 1 patient in the T3 interval. No other complications were reported. Conclusions PV isolation by visually guided LBA is a safe procedure even during the learning curve. The system is user friendly and procedural time and fluoroscopy time reduced after a limited number of procedures.