Background: Cryoballoon pulmonary vein isolation (PVI) is increasingly used for atrial fibrillation (AF) ablation. The second-generation cryoballoon (CB) (Arctic-Front Advance, Medtronic) features a widened zone of cooling and enables shorter cryo-ablation time. An intraluminal 8-poles circular catheter provides PV recording during cryo-ablation. Phrenic nerve palsy (PNP) may be related to ablation duration. We aimed to analyze the effectiveness, safety and outcomes of a PV-potentials guided cryo-ablation duration, rather than the 4-min current recommendation.
Methods: When PV potentials could be visualized during freezing, CB ablation duration was set to 2 minutes after their disappearance. CB ablation was applied for 3 minutes to the other veins. Acute procedural success was assessed by disappearance of PV potentials and by showing entrance block into the PV`s when pacing the LA. The right phrenic nerve was paced during right PV’s ablation to detect nerve injury. Recurrence of AF was evaluated by patients’ symptoms and by 24-h Holter monitoring.
Results: Thirty-two consecutive patients (26 males, mean age= 56.8±11.6) underwent PVI for paroxysmal or early persistent AF using the current protocol. PVP were demonstrated in 106 veins. After a mean of 1.35 freeze cycles per vein, all PV’s were isolated, 90 (85%) during the first freeze. Median time to PVI was 39 sec (IQR=26-59). Mean procedure and fluoroscopy times were 132±33 and 33±19 min, respectively. By the end of the procedure, PV isolation was demonstrated in all 130 veins. Only one patient had phrenic nerve palsy which subsided within 30 minutes. One patient had a pericardial effusion requiring pericardiocenthesis without clinical sequelae. At a mean 12-month follow-up, 26 patients (82.5%) were free from AF or any atrial arrhythmia.
Conclusion: Adjusted CB ablation duration to the disappearance of PV potentials shows a good acute procedural success and 1-year freedom of AF, with an apparently lower rate of PNP.
