Improved In Vivo Performance of Second‐Generation Cryoballoon for Pulmonary Vein Isolation

INTRODUCTION: A novel cryoballoon with improved refrigerant distribution promises better pulmonary vein (PV) isolation success rate without sacrificing the technology's safety profile. This study aimed to compare the Arctic Front® (AF) balloon to the new Arctic Front Advance™ (AFA). METHODS AND RESULTS: Twenty pulmonary PVs from 10 healthy dogs weighing 29.8 ± 1.1 kg were assigned to ablation with AF and AFA, using a 23 mm or 28 mm balloon. A single 4-minute ablation was performed in each vessel, with no phrenic nerve monitoring. The Achieve™ mapping catheter was used to confirm acute isolation. Thirty days post-treatment the ablation sites were assessed for electrical PV isolation and ablation completeness via gross and histological examination. The phrenic nerve, PVs, lungs, esophagus, kidneys, and brain were collected for evaluation of potential damage. A preprocedural and prenecropsy CT were performed to assess incidence of PV stenosis. All 10 PVs were fully isolated with AFA; 6 of 10 PVs were fully isolated with AF. In all cases, lesion gaps with AF are believed to stem from inadequate cooling of the most distal balloon segment that was in contact with the unablated PV tissue. No untoward findings were detected on gross examination of the heart, esophagus, kidneys, brain, or PVs. One phrenic nerve had cross-sectional ablation associated with an AFA 23 mm balloon. Superficial regions of subpleural lung fibrosis were noted adjacent to 7 PVs. CONCLUSIONS: PV isolation and lesion completeness were improved with Arctic Front Advance, while no unexpected findings were found related to safety.