Ablation procedure

Catheter ablation was performed as described previously²¹. An electrophysiological study was performed in the post-absorptive state under light sedation. Trans-esophageal echocardiography was performed to exclude the possibility of LA appendage thrombus just before ablation in all patients. After internal jugular and femoral vein punctures, a heparin bolus (100 U/kg) was administered, and continuous heparin infusion provided thereafter to maintain an activated clotting time of 250–350 s. A diagnostic duodecapolar catheter was placed in the coronary sinus via the jugular vein. Three long sheaths were inserted through the femoral vein and introduced in the LA through a single transseptal puncture guided by intracardiac echocardiography. Eicosapolar circumferential catheter (Lasso 2515, Biosense Webster, Diamond Bar, CA, USA) and multi-spline mapping catheter (PentaRay, Biosense Webster, Diamond Bar, CA, USA) were introduced in the LA through the transseptal long sheaths. All imaging was performed using a biplane flat-panel detector angiographic suite (Allura Xper FD10/10 angio system; Philips Healthcare, Best, Netherlands). Electroanatomical mapping was performed using the CARTO3 mapping system (Biosense Webster, Diamond Bar, CA, USA). Radiofrequency ablation was performed with an irrigated catheter (EZ Steer Thermocool, Biosense Webster, Diamond Bar, CA, USA) using 0.9% normal saline and a point-by-point technique. Extensive encircling pulmonary vein isolation (EEPVI) was performed in patients with paroxysmal AF, and entrance and exit blocks documented in all cases using Lasso2515 and PentaRay multipolar catheters. In addition to EEPVI, patients with persistent AF received LA posterior wall isolation; additional linear ablation along the LA roof to connect the left superior pulmonary vein to the right superior pulmonary vein and linear ablation along the LA floor to connect the inferior margin of the left inferior pulmonary vein to the right inferior pulmonary vein were performed to gain a block into the posterior wall. Bidirectional block was confirmed across all linear ablations using differential pacing techniques. If common atrial flutter was induced by atrial burst or extra stimulus pacing, cavotricuspid isthmus line ablation was performed in patients with both paroxysmal AF and persistent AF.