Patients were treated with video-assisted thoracoscopy under general anesthesia. PVI was performed from the epicardial side with a bipolar RF ablation clamp (AtriCure). At least 2 overlapping applications around each of the ipsilateral veins were made, and isolation was confirmed by the absence of PV potentials and exit block during pacing. An additional application was made in the interatrial Waterston groove in the right side to isolate the ganglionic plexi from the atria. On the left side, the ligament of Marshal was cut, but no additional ablation of ganglionic plexi was pursued.

The RevealXT (implantable loop recorder) was implanted in the parasternal area of the chest. The requirement for defining the exact final position was an R-wave amplitude ≥0.4 mV assessed through the Vector Check.

Externally-irrigated tip (5-mm tip, Celsius Thermo-Cool, Biosense Webster, Diamond Bar, CA, USA). Temperature-controlled RF delivery was performed with a maximum power output of 50 W and temperature limit of 50 C. The catheter was irrigated using 0.9% saline infusion at a flow rate of 20-40 mL/min during RF delivery and 2 mL/min between applications using a commercially available pump (Cool Flow, Biosense Webster). The RevealXT (implantable loop recorder) was implanted in the parasternal area of the chest. The requirement for defining the exact final position was an R-wave amplitude ≥0.4 mV assessed through the Vector Check.