Transcutaneous Regulation for Atrial Prevention in Postoperative Atrial Fibrillation Following OPCAB

Inclusion Criteria: 1. Age 18 years or older. 2. Scheduled to undergo elective off-pump coronary artery bypass grafting (OPCAB) for coronary artery disease with multivessel coronary artery disease. 3. Sinus rhythm on the preoperative baseline electrocardiogram, with no history of atrial fibrillation or other clinically significant arrhythmias. 4. Able and willing to provide written informed consent and comply with the study intervention and follow-up procedures. 5. Expected postoperative hospital stay of at least 7 days to allow postoperative atrial fibrillation monitoring. Exclusion Criteria: 1. History of atrial fibrillation or other arrhythmias requiring antiarrhythmic therapy. 2. Emergency OPCAB surgery or intraoperative conversion to on-pump coronary artery bypass grafting. 3. Concomitant cardiac surgery, such as valve surgery, or hybrid cardiac procedures. 4. Vagus nerve-related disorders, epilepsy, active ear infection, or implanted electrical devices such as a pacemaker or implantable cardioverter-defibrillator. 5. Severe comorbidities, including severe renal dysfunction (estimated glomerular filtration rate \<30 mL/min/1.73 m²), active malignancy, current immunosuppressive therapy, or chronic inflammatory disease. 6. Inability to tolerate auricular stimulation, including significant skin allergy or intolerance, or anticipated poor adherence to the study procedures. 7. Expected survival of less than 12 months or inability to complete follow-up.