Postoperative Atrial Fibrillation (POAF) is one of the most common complications following coronary artery bypass grafting (CABG) occurring to 20% - 40% of patients. It is associated with prolonged hospitalization, increased hospital costs, increased complications and mortality rate.

Despite the use of Beta Blockers, approximately 20% of patients develop atrial fibrillation following CABG surgery, suggesting a role for polymorphism in the genes The aim of the present study is to determine the minor allele frequency of some of the genes that affect the beta blockers' response and to determine the association between polymorphism in these genes and the occurrence of postoperative atrial fibrillation after coronary artery bypass grafting in Egyptian patients receiving perioperative beta blockers.

Inclusion Criteria:

1. Age above 18 years.
2. Candidates for CABG surgery without a concurrent valve surgery.
3. Patients receiving perioperative beta blockers before new onset of postoperative AF.

Exclusion Criteria:

1. Patients who have either persistent or permanent AF, atrial flutter or atrial tachycardia on ECG obtained on the day of the operation.
2. Serum creatinine >2 mg/dL before the surgery.
3. Uncontrolled thyroid disease.
4. Recent treatment with amiodarone before the occurrence of POAF

Egyptian patients undergoing Coronary Artery Bypass grafting Surgery