A 78-year-old man with a highly symptomatic left atrial tachycardia, refractory to medical therapy, was referred for radiofrequency catheter ablation. Using a double trans-septal technique, two long sheaths were placed across the interatrial septum into the left atrium. Using a 64-electrode non-contact three-dimensional mapping technique, the left atrium was reconstructed and the focus localized to the right superior pulmonary vein ostium. Radiofrequency energy was applied and eliminated the ectopic focus. In summary, a three-dimensional non-contact mapping catheter can facilitate ectopic left atrial tachycardia ablation.