Cryoballoon Ablation of Pulmonary Veins After Failed RF Ablation in Patients With Paroxysmal AF

In Cryo group, 28mm balloon was introduced into the PV ostium with the best possible occlusion of the PV. Every step was controlled by fluoroscopy. Cryoenergy was applied for maximal 6 minutes per application for 2 times, resulting in a circumferential ablation lesion. Before the right superior vein was treated, a quadripolar catheter was placed in the superior vena cava to continuously stimulate the right phrenic nerve during cryoapplication. The application was stopped immediately in the case of diminished diaphragm movements.

n RF group, reisolation of the PV was performed by identifying the breakthrough site. Radiofrequency energy was delivered at 43°C, 35 W, 0.5 cm away from the PV ostia at the anterior wall, and was reduced to 43°C, 30 W, 1 cm away from the PV ostia at the posterior wall, with a saline irrigation rate of 17 mL/min. Each lesion was ablated continuously until the local potential amplitude decreased by \>80% or RF energy deliveries exceeded 40 s.