A total of 12 patients with a known diagnosis of Atrial Fibrillation who have previously undergone Atrial RF ablation will be enrolled in the study. Patients will be asked to swallow the OFDI capsule while being unsedated. The capsule is attached to a tether that allows the capsule operator to navigate the capsule as it progresses down the esophagus using natural propulsion called peristalsis as well as to bring it back up to pulled out of the mouth when the procedure is done.
As the capsule progresses down the esophagus, multiple, two dimensional, microscopic cross- sectional images of the esophagus are acquired.
