Temporary Autonomic Blockade to Prevent Atrial Fibrillation After Cardiac Surgery

In this study, the investigators aim to determine whether injecting botulinum toxin into epicardial fat pads is efficacious and safe for decreasing postoperative atrial fibrillation (POAF) after cardiac surgery. The investigators will test the hypothesis that botulinum toxin injected into the epicardial fat pads reduces POAF and length of stay (LOS) without increasing adverse events. This will be a prospective randomized trial of 130 patients undergoing coronary artery bypass graft (CABG), valve surgery or CABG + valve surgery with cardiopulmonary bypass. Patients will be randomized to receive either botulinum toxin (50 units per fat pad, n=65) or normal saline/placebo (1 mL per fat pad, n=65) injected into epicardial fat pads. All patients will receive standardized anesthetic, surgical, and post-surgical care. The primary outcome in this study will be time to occurrence of in-hospital POAF. Based on previous work and a pilot trial showing a pronounced reduction (relative risk reduction 77%) in POAF after injecting botulinum into the epicardial fat pads, the investigators anticipate a significant reduction in the risk for POAF with epicardial botulinum in this cohort, which includes valve surgery patients.