Reentrant atrial tachycardias may occur after mitral valve surgery. These usually involve the left atrium or the lateral wall of the right atrium around the atriotomy scar.The purpose of this study was to test whether ablation could eliminate atrial tachycardia after mitral valve repair.Three patients (two men, one woman; mean age 57 ± 12 years) were studied 48 ± 38 months after mitral valve repair. In all cases, the surgical approach involved a transseptal incision. Tachycardia mapping was performed using multipolar catheters and the three-dimensional electroanatomic mapping system. The mean flutter cycle length was 313 ± 21 ms. All patients had dual-loop reentry with one circuit around a septal scar and the other circuit around the tricuspid annulus.Successful radiofrequency ablation of the septal circuit was performed between the scar and the superior tricuspid annulus in all three cases.After mitral valve repair using a transseptal incision, dual-loop reentry may occur around the septal scar and the tricuspid annulus. Successful ablation may be achieved with an ablation line between the scar and the tricuspid annulus.