Atrial fibrillation (AF) is a major health burden in the aging population, and postoperative AF (POAF) is a common complication following coronary artery bypass grafting (CABG). Lysine crotonylation regulates protein function, but its role in POAF remains unclear. We performed 4D label-free quantitative crotonyl-proteomic analysis on right atrial tissues from POAF and sinus rhythm (SR) patients to explore the pathogenesis of POAF.