Radiofrequency ablation of a posteroseptal accessory pathway via the middle cardiac vein in a six-year-old child.

Although radiofrequency ablation is highly successful in patients with the Wolff-Parkinson-White syndrome, certain pathways remain refractory to ablation. In particular, subepicardial pathways often fail ablation via an endocardial approach. In adult patients, left-sided subepicardial pathways have been treated successfully using energy delivery within the coronary sinus. To document the safety and efficacy of this approach in children, we present the case of a 6-year-old boy who underwent radiofrequency ablation of a posteroseptal pathway via energy delivery within the middle cardiac vein. Follow-up study showed no evidence of recurrence or gross coronary vascular injury.