Lessons from radiofrequency redo-procedure after cryoballoon pulmonary vein isolation for paroxysmal atrial fibrillation.

Background: To gain further insights into mechanisms leading to atrial fibrillation (AF) recurrence after a first ablation procedure using cryoballoon technique, the data collected during redo procedure were analyzed. Methods and Results: From a total of 112 patients who underwent cryoballoon pulmonary vein isolation (PVI) for paroxysmal AF, 44 had a second ablation procedure using radiofrequency catheter, because of recurrent atrial arrhythmia. PV reconduction was observed in 109 of the 171 initially isolated veins (64%). Conduction recovery was found, respectively, at the left inferior PV, right inferior PV, right superior PV and left superior PV in 35 patients (80%), 26 patients (67%), 23 patients (52%) and 17 patients (39%). The mean number of reconnected PVs per patient was significantly lower with the 23-mm cryoballoon as compared to the 28-mm. Conduction gaps were focal and located at inferior parts of inferior veins and at the ridge between left atrial appendage and left veins. Mean procedure and fluoroscopy time were 109+/-32 min and 14.7+/-8.3 min, respectively. A 3-D mapping system was used in only 8 patients (18%). Conclusions: Atrial arrhythmia recurrences following cryoballoon PVI were associated with focal PV reconnections, occurring at preferential anatomical sites. These gaps were readily ablated with focal radiofrequency delivery, explaining the lack of need of 3-D mapping system and short procedure time. These results do not support the use of cryoballoon to perform redo procedures.