"UNMASKING Study" For Atrial Fibrillation Recurrences Typing in Early Postoperative Period

The left atrium (LA) and PVs were explored through a transeptal approach. Real-time 3D LA maps were reconstructed by using a nonfluoroscopic navigation system (CARTO, Biosense-Webster Inc.). The ipsilateral left and right PVs were encircled in one lesion line by circumferential PV isolation. 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 speed of 17 mL/min. The endpoint of ablation was PV isolation; this was confirmed when Lasso mapping showed the disappearance of all PV potentials or the dissociation of PV potentials from LA activity. The ICM (Reveal XT, Medtronic Inc) was implanted the day of the ablation procedure or 1 week before.The Reveal XT 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.