Patient population
We identified 53 consecutive patients at a single experienced electrophysiology center who underwent first time RF ablation for persistent AF. Of these, 27 were cardioverted then mapped and ablated in sinus rhythm with atrial pacing, and 26 were mapped and ablated in AF with ventricular pacing. Pacing was performed at a cycle length of 500-600ms, regardless of pacing site. All procedures were performed under general anesthesia with high frequency jet ventilation. Electroanatomical mapping was performed using either the circular Lasso® or five-spine PentaRay®mapping catheter and the CARTO3® mapping system, version 4 (Biosense Webster Inc., USA). Radiofrequency ablation was performed using the ThermoCool SmartTouch®force-sensing catheter (Biosense Webster Inc., USA) using point-by-point ablation at a power of 50W. All patients underwent pulmonary vein isolation (PVI) via wide antral circumferential ablation of the left and right pulmonary veins, as well as posterior wall isolation (PWI) via superior and inferior posterior wall lines connecting the PVI lesion sets. Additional ablation of the left and right carinas and/or residual electro-active areas within the posterior wall were performed at the discretion of the operator. VisiTag lesion stability settings were set to 2mm and 5s. Electrical isolation, including entrance and exit block, was confirmed using differential pacing and adenosine administration.