We performed 4D-labelfree quantitative proteomics analysis of right atrial appendage tissues from 5 patients with atrial fibrillation (AF) and 5 patients with sinus rhythm (SR) after CABG. A total of 2179,559 spectrums and 48,047 peptides were detected by mass spectrometry. Further, we identified 5002 proteins, of which the number of comparable proteins was 4166. Finally, compared with SR group, 108 proteins were up-regulated and 25 proteins were down-regulated in AF group (AF/SR > 1.5, P < 0.05).