Objective To elucidate the electrophysiological and substrate characteristics of the left atrial(LA)in patients with persistent atrial fibrillation(Pers-AF),for guiding radiofrequency ablation strategies of Pers-AF.Methods Eighty patients with Pers-AF,and thirty patients with paroxysmal AF(Paro-AF)were compared with ten age-matched controls with left accessory pathways(Control group).High-density 3-dimensional electroanatomic maps were created during the sinus rhythm and the LA was divided into 7 segments f...