3. The standard approach to atrial fibrillation involves electrical isolation of the pulmonary veins (PVI) from the rest of the atrium chamber. This involves moving a 3.5mm tip ablation catheter point to point around the PV structures until an encircling ablation line is formed. This can be made difficult by not knowing if the tip is in good contact with the atrial tissue. In addition the esophagus is a posterior lying structure and injury to the esophagus by ablating the overlying tissue has been reported, at times fatal;