NPPB and diabetes mellitus: The definition of high risk for developing post-operative AF was based on the ESC guideline [2] which included at least one of the following: (1) clinical risk factors (such as age at least 65 years, history of AF, COPD, diabetes), (2) surgical risk factors [such as coronary artery bypass grafting (CABG), mitral valve surgery, lobectomy or pneumonectomy] (3) biomarkers and imaging [such as elevated N-terminal pro-B-type natriuretic peptide (NT-proBNP), enlarged LA], and (4) risk scores (such as CHA2DS2-VASc score).