Impact of Cryoballoon Freeze Duration on Long-Term Durability of Pulmonary Vein Isolation: ICE Re-Map Study

Objectives: This study sought to evaluate the durability of pulmonary vein isolation (PVI) after 2 different freeze durations by using time-to-effect guided (ICE-T) second generation cryoballoon (CB2) ablation strategy in patients with atrial fibrillation (AF) undergoing repeat procedure.

Background: CB2 represents a powerful technology for PVI. Recently, the ICE-T CB2 ablation strategy targeting a 240-s single freeze demonstrated fast and efficient PVI. To further optimize safety and efficacy, a shortened 3-min freeze duration has been suggested, but PVI durability remains unclear.

Methods: Between May 1, 2013 and December 31, 2017, all CB2 ablations followed the ICE-T concept (target freeze: 240 s or 180 s). Patients undergoing a second procedure for arrhythmia recurrence were analyzed. Two groups were defined based on the index freeze duration (group A: 240 s vs. group B: 180 s). In all repeat procedures a 3-dimensional left-atrial map was obtained. Durability of PVI and localization of conduction gaps were compared.

Results: Of 788 total patients, 106 (13%) underwent a second procedure (group A: 80 of 604 vs. group B: 26 of 184) after a mean of 377 days. There was no difference regarding PV occlusion and time-to-isolation in the index procedure between the 2 groups. No major complications occurred. During the second procedure, significantly more patients demonstrated durable isolation of all PV in group A (61% vs. 35%; p = 0.02) along with a significantly increased rate of PVI durability (88% vs. 69%, per vein; p < 0.001). Left-sided PV did significantly benefit from 240-s freeze (reconnection left superior PV: 6% vs. 27%; p = 0.004, left inferior PV: 14% vs. 39%; p = 0.006).

Conclusions: The ICE-T ablation strategy is associated with a high rate of durable PVI in patients with arrhythmia recurrence. Target freeze duration of 240 s versus 180 s is associated with significantly increased lesion durability, particularly at left-sided PV, without increasing complications.