Initial clinical experience of pulmonary vein isolation using the ultra-low temperature cryoablation catheter for patients with atrial fibrillation

Background: The iCLAS ultra-low temperature cryoablation (ULTC) system has recently been brought to the market. A combination of a newly exploited cryogen and interchangeable stylet enables flexible and continuous lesion creation in atrial fibrillation (AF) ablation. The use of an esophageal warming balloon is recommended when using the system to reduce the potential for collateral esophageal injury.

Objective: To describe the initial clinical experience when using ULTC in the AF treatment without general anesthesia (GA).

Methods: Consecutive patients undergoing AF ablation using ULTC under deep sedation without GA were enrolled. We assessed the procedural data focusing on "single-shot isolation" defined as successful pulmonary vein (PV) isolation after the first application. Esophagogastroduodenoscopy was systematically performed the day after ablation.

Results: A total of 27 AF patients (67% paroxysmal AF) were analyzed. Onehundred four out of 106 PVs (98.1%) were isolated solely using ULTC. The mean procedure time was 79 ± 30 min. The mean number of applications per PV was 2.6 ± 1.0. Single-shot isolation was achieved in 57 PVs (54%) varying across PVs from left superior to inferior PVs (40%-64%). The single procedure 6-month recurrence-free rate was 84%. No major complication (cerebrovascular event, pericardial effusion/tamponade, esophageal damage on esophagogastroduodenoscopy) occurred. A single transient phrenic nerve palsy occurred during the right superior PV ablation, which had recovered by the 3-month follow-up appointment.

Conclusions: AF ablation using the novel ULTC system seemed feasible without GA and enabled a >50% single-shot isolation rate. The promising safety profile has to be confirmed in large-scale studies.