Group 2. GP ablation. The anatomic areas of GP are identified in the right and left atrium. Anatomic locations of GP were considered around the PV: anterior right (ARGP), inferior right (IRGP), left superior (LSGP), and left inferior GP (LIGP). In addition the following GP were considered: The GP at the crux of the left atrium which is probably near or in continuation with the IRGP (2-3 cm below the lower edge of RIPV), expanding both toward the mitral annulus and inferior aspect of the LA posterior wall (cruxGP). This GP was also approached from the crux of the RA, behind the tendon of Tadaro/Eustachian ridge and the coronary sinus ostium. The GP at the septal-posterior aspect of the junction of the RA with the SVC (this GP may actually correspond to the 3rd fat pad located at the junction of SVC-RA-right PA-aorta).14-18 Following anatomic orientation, precise determination of the location of parasympathetic GP is accomplished by high-frequency stimulation.19 Patients are deeply sedated with diamorphine and diazepam without intubation, and high-frequency stimulation is delivered with a Grass stimulator at 1,200 bpm (20 Hz) with a pulse width of 10 ms at 20 V. A predominant parasympathetic response is defined as induction of AV block (> 2 sec) and hypotension or prolongation of the R-R interval by >50% during AF, following a 5 seconds application of high-frequency stimulation.19 Before applying high-frequency stimulation to inferior GP, extra care is taken to ensure that the catheter tip is not on the annulus to avoid induction of ventricular fibrillation. Verification of catheter position is accomplished by examination of recorded electrograms and anatomic location on both lateral views on CARTO. The sequence of GP ablation is: LS GP, LI GP, ARGP GP, IRGP, right anterior GP and the crux GP situated in the RA. After each ablation lesion (46°C, 35W for 60 seconds, 17 mL/min), parasympathetic response is reassessed by high-frequency stimulation. End-point for radiofrequency delivery is abolition of parasympathetic response. Following specific GP ablation, anatomical ablation is performed as previously described, in a way that the designated anatomic areas of GP are ablated.