Cryoballoon ablation during atrial fibrillation is associated with faster temperature drop and lower freezing temperatures.

PURPOSE: Our aim was to analyse the temperature behaviour during second-generation cryoballoon ablation (CB-A) in patients with ongoing atrial fibrillation (AF) compared with those in sinus rhythm (SR).

METHODS: Consecutive patients with drug-resistant AF who underwent pulmonary vein (PV) isolation by CB-A from April 2014 to May 2015 were analysed. The exclusion criteria were any contraindication for the procedure including the presence of an intracavitary thrombus, uncontrolled heart failure, contraindications to general anaesthesia and cardioversion to SR during the ablation procedure.

RESULTS: A total amount of 323 consecutive patients having undergone PV isolation by means of CB-A (male 66 %, age 56.1 ± 13.4 years) was enrolled. During ablation in the left-sided PVs, time needed to reach -20°, -30° and -40° was significantly shorter in patients with AF than those in SR. During ablation in the right superior pulmonary vein (RSPV), time to reach -30° and -40° was also significantly longer in patients with AF; during ablation in the right inferior pulmonary vein (RIPV), although the temperature drop was faster in the AF group, times needed to reach -20°, -30° and -40° were not significantly prolonged compared with those in the SR group. Temperatures attained at 60 s, and minimal temperatures were also significantly lower in the AF group during all PV ablations except RIPV.

CONCLUSIONS: The temperature drop during AF cryoablation was significantly faster and attained significantly lower freezing degrees in patients with ongoing AF during the procedure compared with those in SR. This finding resulted markedly significant during each PV isolation except for RIPV cryoablation.