Once Versus Twice Bisoprolol Dosage Regimen in Prevention of Atrial Fibrillation Post Coronary Artery Bypass Graft Surgery

Inclusion Criteria: Adult patients: 18 to 65 years old Diagnosed with coronary heart disease or myocardial infarction and scheduled for coronary artery bypass surgery Exclusion Criteria: History of Ventricular arrhythmia, atrial fibrillation, atrial flutter, left bundle block, AV block grade II/III History of Sick sinus syndrome, sinoatrial heart block History of valve replacement Permanent Pacemaker LVEF less than 30% Unstable Heart failure Cardiogenic shock Sustained systolic blood pressure less than 100 mmHg or HR less than 50 bpm at recruitment Severe chronic obstructive airway disease Severe asthma unless was on previously tolerated bisoprolol dose Uncontrolled diabetes mellitus unless was on previously tolerated bisoprolol dose Pregnant/Lactation Previous recent stroke Creatinine clearance less than 30 ml/min End stage liver disease (liver cirrhosis) Drug dependance history Untreated phaeochromocytoma Vasospastic angina Thyrotoxicosis History of advanced staged of peripheral vascular disease Hypersensitivity Patients on any other beta-blocker other than bisoprolol Patients on bisoprolol higher than 5 mg/day.