There is limited data available on the safety and efficacy of the second-generation cryoballoon (CB-2) for cryoablation of atrial fibrillation (Cryo-AF). We evaluated the procedural, biophysical, and clinical outcomes of Cryo-AF in a large patient cohort using CB-2 as compared with the first-generation cryoballoon (CB-1).

Three-hundred and forty consecutive patients undergoing Cryo-AF with CB-1 (n = 140) and CB-2 (n = 200) were retrospectively evaluated.

Paroxysmal AF was more prevalent in CB-1 (86 %) versus CB-2 (72 %) (p = 0.001). During Cryo-AF, the mean balloon temperature was lower with CB-2 at 30 s (8 versus −4 °C; p < 0.001) and 60 s (−26 versus −32 °C; p < 0.001) with equivalent nadir temperatures (both at −50 °C; p = 0.542). With CB-2, time-to-nadir temperature was shorter (232 versus 209 s; p < 0.001) and thaw times were longer (47 versus 53 s; p < 0.001). Acute pulmonary vein (PV) isolation rate was higher with CB-2 (92 versus 98 %; p = 0.036) despite reduced cryoablation time (61 versus 47 min; p < 0.001) and freeze area-under-the-curve (−155,044 versus −116,740 s °C; p < 0.001). With CB-2, procedure time (209 versus 154 min; p < 0.001) and fluoroscopy time (42 versus 27 min; p < 0.001) were shorter, with similar acute/long-term adverse events (AEs) and freedom from AF at 6, 9, and 12 months (89, 86, and 82 %) during 16 ± 8 months of follow-up. However, CB-2 was associated with lower PV reconnection rates at redo ablation (30 versus 13 %; p = 0.037).

With CB-2, acute and long-term PV isolation rates were higher despite shorter ablations, faster balloon cooling, and longer thaw times, with similar AE rates and freedom from AF.