Catheter ablation of ventricular tachycardia is often difficult in patients after surgery for CHD. In patients with a ventricular septal defect patch, it is necessary to decide which ventricular side is appropriate for catheter ablation. In this article, we report a case of successful point catheter ablation of re-entrant ventricular tachycardia. Identification of the ventricular septal defect patch using intra-cardiac echocardiography was useful.