Objective:To observe the outcomes of radiofrequency ablation in patients with atrial tachyarrhythmia (ATa) after circumferential pulmonary vein isolation (CPVI),so as to discuss the related mechanism.Methods:A total of 64 patients underwent mapping and ablation using an electroanatomic mapping system (CARTO) at a mean of (3.7±2.4) months after the first CPVA procedure.Results:A total of 78 types of ATa were mapped, including 30 (38.5%) with re-entry mechanism and 48 (61.5%) with focal mechanism.Among reentrant ATa 12 had common atrial flutter and 18 had left atrial re-entry; the reentrant circuits were related to the mitral isthmus,the anterior wall of the left atrium,and the gaps on previous encircling lines.The tachycardias were unstable in 2 patients and were not mapped.Catheter ablation was successful in 56 of the 64 patients (87.5%),and cardioversion was needed in 8 patients to achieve sinus rhythm.During a mean follow-up of 13-21（16.5±2.9）months,60 (93.8%) cases no longer had ATa.Conclusion:ATa after CPVA can have macro-reentrant and focal mechanisms.These arrhythmias can be successfully mapped and ablated with an electroanatomic mapping system.