Effect of Left Posterior Pericardiotomy for the Prevention of POAF

Inclusion Criteria: * patients who are planned to undergo coronary artery bypass grafting * patients aged ≥19 years Exclusion Criteria: * patients who are planned to undergo other concomitant cardiac procedures (e.g. valve procedures, aorta procedures) * patients who undergo coronary artery bypass grafting using cardiopulmonary bypass * patients who are documented with paroxysmal, persistent, or permanent atrial fibrillation before operation * patients who have a history of cardiac surgery * patients who have a history of pericardial disease * patients who have severe adhesion at left pleural cavity which precludes effective left posterior pericardiostomy * patients who refuse to participate in this study