The case is presented of a five-year-old boy with Wolff-Parkinson-White syndrome, who had
undergone three surgical palliations because of congenitally corrected transposition of the great
arteries, ventricular septal defect and pulmonary trunk near-atresia. Successful and uncomplicated
radiofrequency catheter ablation of an accessory pathway located across the systemic
atrioventricular valve ring was performed. The procedure was motivated by forthcoming corrective
surgery, which would preclude venous access to the heart. This case emphasizes the
need for precise timing of ablative therapy in such patients and shows that surgery itself may
facilitate catheter ablation. (Cardiol J 2007; 14: 500-503