The authors report the case of a 57-year-old woman with Ebstein's anomaly and atrial septal defect. She was referred to their hospital for treatment of refractory paroxysmal wide QRS tachycardia. Her 12-leads ECG in sinus rhythm showed ventricular preexcitation of type B Wolff-Parkinson-White syndrome. In a baseline electrophysiological study, a wide QRS tachycardia with right bundle branch block configurations was induced. This tachycardia was orthodromic atrioventricular reciprocating tachycardia with a right inferior accessory pathway. Radiofrequency current was successfully delivered at the inferior site of the atrialized right ventricle. Radiofrequency catheter ablation seems to be useful for supraventricular tachycardia in patients with Ebstein's anomaly and atrial septal defect.