Abstract: Systems and methods for photodynamic ablation of cardiac tissue via an esophagus are disclosed. An exemplary system includes an ablation catheter having an expandable distal end for securing the ablation catheter in the esophagus. The distal end of the ablation catheter contains at least one light source operable to activate a photodynamic substance delivered to the target area of the cardiac tissue to be ablated and form a lesion. The system also includes at least one feedback device contained in the distal end of the ablation catheter. The at least one feedback device provides feedback for at least one of: positioning a distal end of an ablation catheter in a desired position in the esophagus adjacent a target area of the cardiac tissue to be ablated, forming an adequate lesion, and assessing lesion formation.