ATRIAL FIBRILLATION FOLLOWING CORONARY ARTERY BYPASS GRAFT SURGERY

Objective: To know the frequency of atrial fibrillation (AF) after coronary artery bypass graft surgery and the risk factors which predispose these patients to develop post-operative AF.Material and Methods: This prospective, observational, analytic study was carried out at National Institute of Cardiovascular Diseases Karachi, from January 2001 to January 2002. It included 200 patients undergoing elective or emergency coronary artery bypass graft (CABG) surgery without concurrent valvular heart disease, prior history of AF, ventricular arrhythmias or redo CABG surgery. All patients underwent CABG and were followed for three weeks for incidence of AF. Patients who developed AF (group A) were compared with patients without AF (group B) for different variables. Univariate analysis was done using Studentʹs t-test for continuous variables and Chi-square test for categoric variables.Results: The mean age was 52.78 + 8.32 years. The average bypass time and cross clamp time were 83.20 (SD ± 18.73) minutes and 29.73 (SD ± 7.25) minutes respectively. The mean ejection fraction was 49.34%. The median number of grafts was three. The frequency of AF was 12 (6%). Univariate analysis revealed that advanced age, male sex, right coronary artery lesion, prolonged bypass time and low ejection fraction were statistically significant risk factors (p< 0.005).Conclusion: AF is a common, but potentially preventable, complication following CABG surgery. The Advanced age, low ejection fraction, prolonged cross clamp and bypass time are the important risk factors which may predispose these patients to develop postoperative atrial fibrillation.