Abstract: To investigate the feasibility and efficacy of a stepwise ablation procedure in treatment of atrial fibrillation(AF) on the basis of circumferential pulmonary vein(PV) ablation guided by a three-dimensional mapping system(Carto). MethodsTwelve patients with drug-refractory paroxysmal (n=10) and persistent (n=2) atrial fibrillation were subjected to three-ablation stages during one session: circumferential ablation around the pulmonary vein antrum， segmental pulmonary vein ablation, and ablation of complex fractionated atrial electrograms (CFAEs). Endpoint of the procedure was a non-inducibility of AF at any stage or completion of all three-ablation stages. ResultsTen patients with a paroxysmal AF had a non-inducible AF at the end of the procedure: seven patients after the first stage, two after the second and one after the third. Two patients with a persistent AF who remained AF after all stages required an external cardioversion. Three patients had a recurrent AF within two days, but were free of recurrent AF after further follow-up. One patient with a paroxysmal AF and typical atrial flluter(AFL) had a recurrent AFL and was free of recurrent AF. During 10±4 months of follow-up, all patients were free of recurrent AF or had left atrial arrhythmias without an anti-arrhythmic drug therapy, and no complications occurred. Average radiofrequency energy delivery, fluoroscopy time and procedure time were (38±11) min, (37±11) min and (3.0±0.5) h, respectively. ConclusionA stepwise ablation procedure on the basis of circumferential pulmonary vein ablation with the AF noninducibilty as a endpoint is effective and safe. Circumferential pulmonary vein ablation alone is enough for paroxysmal AF treatment, while it combined with segmental pulmonary vein ablation and CFAEs ablation may result in high successful rates.

Key words: Atrial fibrillation, Catheter ablation, Pulmonary vein