ObjectiveTo compare clinical outcomes between biatrial ablation and right atrial ablation in the surgical treatment of atrial fibrillation (AF)for adult patients with atrial septal defect (ASD). MethodsClinical data of 47 patients with ASD and AF who underwent surgical ASD repair and radiofrequency ablation from January 2007 to December 2012 were retrospectively analyzed. There were 20 male and 27 female patients with their age of 35-76 years. AF duration ranged from 3 months to 15 years. There were 18 patients with persistent AF and 29 patients with long-standing persistent AF. There were 10 patients with mild-to-moderate or more severe mitral regurgitation (MR), and 28 patients with mild-to-moderate or more severe tricuspid regurgitation (TR). According to different surgical strategies, all the 47 patients were divided into 2 groups. In right atrial ablation group, there were 19 patients who received ASD repair and right atrial ablation. In biatrial ablation group, there were 28 patients who received ASD repair and biatrial ablation. For patients with mild-to-moderate or more severe MR or TR, concomitant mitral or tricuspid valvuloplasty was performed. All the patients received 24-hour Holter monitoring at 3, 6 and 12 months after discharge, and were intermittently followed up thereafter. ResultsCardio-pulmonary bypass time, aortic cross-clamping time and postoperative hospital stay of biatrial ablation group were significantly longer than those of right atrial ablation group. But there was no statistical difference in postoperative morbidity or recovery between the 2 groups. After heart rebeating, there were 25 patients (89.3%)with sinus rhythm (SR)and 3 patients with junc-tional rhythm (JR), and none of the patients had AF in biatrial ablation group. There were 14 patients (73.7%)with SR, 2 patients with JR and 3 patients with AF in right atrial ablation group. At discharge, 28 patients (100%)in biatrial ablation group had SR, and in right atrial ablation group there were 15 patients (78.9%)with SR and 4 patients with AF relapse (P=0.045). All the patients were followed up for 3-75 months, and there was no death or residual ASD shunt during follow-up. Two patients had mild-to-moderate or more severe MR, and 4 patients had mild-to-moderate or more severe TR. Cumulative SR maintenance rate of biatrial ablation group (87.7%±6.7%)was significantly higher than that of right atrial ablation group (47.4%±11.5%, P=0.003)at 2 years after discharge. ConclusionFor adult patients with ASD and AF, biatrial ablation can produce better clinical outcomes than right atrial ablation without increasing surgical risks.