Atrial fibrillation (a-fib) is one of the most frequently encountered and studied arrhythmias in medicine. The presence of A-fib in the post-operative period of coronary artery bypass graft (CABG) surgery is of particular concern for clinicians as this presents risks of post-operative stroke, hospital readmission, or anticoagulation dilemmas depending on the patient's comorbidities. In this case study, we present 5 patients who were treated with dronedarone prior to undergoing open heart procedures. We subsequently followed each patients clinical course paying close attention for any evidence of post-operative a-fib.