This investigation is a prospective, nonrandomized multicenter clinical trial evaluating the outcome of patients with atrial fibrillation (AF) requiring concomitant open heart surgery plus the Cardioblate Surgical Ablation System using the modified Maze III procedure. The trial population includes patients requiring valve replacements or repairs, atrial septal defect (ASD) repairs, patent foramen ovale (PFO) closure or coronary artery bypass graft (CABG) procedures. The study objectives are to demonstrate that the Medtronic Cardioblate Surgical Ablation System can safely and effectively treat permanent AF patients.