Post-operative atrial fibrillation (POAF) is a major and frequent complication occurring after cardiac surgery, contributing to prolonged intensive care and hospital stays and is associated with several cardiovascular complications. The exact mechanisms and signaling pathways involved in the development of POAF seem to be multifactorial and remain to date incompletely understood. β-blockers and amiodarone are the first line preventive drugs but are partially effective and near 30% of POAF resist to these strategies. In this context, there is some evidence indicating that renin-angiotensin-aldosterone system and Galectin-3 (Gal-3) share signaling pathways in the development of cardiac fibrosis and therefore could be very useful predictive biomarkers of POAF and potentially interesting therapeutic target to prevent POAF occurrence.

The investigators hypothesis is that preoperative plasma aldosterone levels and galectin-3 (Gal-3) expression (in plasma, right atrial appendage or epicardial fat) could be predictive of POAF in patients undergoing elective CABG surgery with preserved LVEF.

Inclusion Criteria:

• Patients hospitalized for planned surgical coronary revascularization +/- aortic replacement valve
• Aged 18 years at least
• Clinically Stable (see criteria for non-inclusion)
• With left ventricular ejection fraction preserved (>50%)

Exclusion Criteria:

• Patient having already AF history
• Patient with primary hyperaldosteronism
• Unstable Patient defined as any cardiovascular event occurred in the previous 30 days

These events are:

• hospitalisation for cardiovascular causes
• appearance or worsening of symptoms consistent with cardiac failure
• appearance or worsening symptoms of coronary
• Patient refusing participation in the study
• Patient unable to provide follow-up visits
• need for concomitant mitral surgery
• Emergency CABG
• Left ventricular ejection fraction (LVEF) < 50%
• Previous heart surgery
• Off pump CABG.

The ALDO-POAF study is an observational, 1-center and prospective pilot study that will enroll patients undergoing CABG ± aortic valve replacement. Patients who had emergency CABG, need for concomitant mitral surgery, left ventricular ejection fraction (LVEF) < 50%, a history of AF or other atrial arrhythmia, unstable angina or heart failure, cardiogenic shock, atrioventricular block, hypothyroidism/hyperthyroidism, previous heart surgery, and off-pump or on-pump beating CABG will be excluded. Approval for this study, including collection of human tissues (right atrial appendage, subcutaneous and epicardial fat) and blood collection, was obtained from the Ethics Committee of Caen University Hospital (Comité de Protection des Personnes Nord-Ouest III, Caen, France) and will be in accordance to the declaration of Helsinki; the details of the study will be explained to the subjects, and written informed consent will be obtained from each patient.