Effect of Preoperative Stellate Ganglion Block on Postoperative Atrial Fibrillation After Coronary Artery Bypass Grafting

Inclusion Criteria: * more than 18 years old * undergoing CABG * Provide informed consent Exclusion Criteria: * History of prior cardiac surgery or atrial fibrillation ablation; * Emergency coronary artery bypass grafting (CABG); * Concomitant cardiac procedures (e.g., congenital heart disease repair, left ventricular reconstruction, valve surgery, or aortic surgery); * Critical preoperative status requiring mechanical or pharmacological support before CABG; * Left ventricular ejection fraction (LVEF) \<35%; * History of atrial fibrillation (defined as a supraventricular tachyarrhythmia characterized by rapid and irregular atrial electrical activity); * Significant mitral valve disease (mitral valve area \<1.5 cm² or regurgitant jet area \<4 cm²), significant aortic valve disease (valve area \<1.5 cm² or regurgitant jet-to-left ventricular outflow tract ratio \>25%); * Severe left atrial enlargement (left atrial anteroposterior diameter \>55 mm); * Poorly controlled hyperthyroidism; * Conditions requiring radiotherapy, chemotherapy, or long-term hormonal therapy; * Patients with known clinical contraindications to stellate ganglion block (SGB).