Abstract
The authors illustrate the successful ablation of a left-sided posterior accessory pathway via a retrograde aortic approach in a patient with coronary ostial atresia associated with persistent left-sided superior vena cava. This is an extremely rare anomaly which should be considered by cardiac electrophysiologists when there is difficulty cannulating the coronary sinus via the right atrial route. Awareness of this route obviates the need for additional venous access.