Successful catheter ablation of ventricular tachycardia in a patient with congenitally corrected transposition of great arteries after double switch operation

Ventricular tachycardia (VT) may cause sudden death late after repair of congenital heart disease. Radiofrequency catheter ablation (CA) of VT can be effective but may be hampered by hypertrophied myocardium or prosthetic material. A 33-year-old man with congenitally corrected transposition of the great arteries (ccTGA) had undergone a double switch operation (DSO) with the combined Mustard and Rastelli procedures when he was 10 years old. He developed sustained VT 16 years after the surgery. An electrophysiological study was performed using a 3D mapping system. During the VT, abnormal fragmented potentials were identified in the right ventricular side near the patch of ventricular septal defect. Radiofrequency energy was delivered at the site with changes in the QRS morphology. Electroanatomical mapping of the left ventricle was performed via a retrograde transaortic approach. Successful ablation of the fractionated potentials was likewise achieved on the left side. We report, to our knowledge, the first case of a successful radiofrequency CA of VT in a patient with ccTGA after a DSO. A slow conduction zone, which was proved to be part of the tachycardia substrate, existed around the patch of ventricular septal defect. Fragmented activities during VT were recorded from both ventricles. The tachycardia circuit was eliminated after ablating the right and left sides of the ventricular septal defect patch.