Incidence and Risk Factors for Atrial Fibrillation after First Coronary Artery Bypass Grafting in Urumiyeh Imam Khomeini Hospital from 2006 to 2008

Background: Atrial fibrillation (AF) is the most common arrhythmic complication following coronary artery bypass surgery (CABG). The incidence of postoperative AF ranges from %10 to %0 and it usually tends to occur within 2 to 4 days after operation. The etiology of AF after cardiac surgery is incompletely understood. Aggres- sive prophylactic intervention should be directed and limited to high risk patients who are most likely to benefit from such procedure. The aim of this study was to identify the frequency of AF and to determine risk factors by using available clinical predictors of postoperative AF after CABG. Methods: The present study was a prospective observational investigation of 300 patients undergoing elective isolated CABG from 2006 to 2008 in Urumiyeh Imam Khomeini Hospital. Peri-operative risk factors were used to develop logistic regression equation in order to predict the development of post-operative AF. Results: A total of 300 patients aged 58± 10 (221 male) were included in the study. The incidence of AF was %12/3(n=37). By univariate analysis, congestive heart failure (P=0.02), and low left ventricular ejection frac- tion (P=0.04) were associated with the development of post-CABG AF. However, in the logistic regression model CHF (OR: 4.87, 95%CI: 1.09-21.6, P=0.038) remained an independent predictor for the development of postoperative AF. On the other hand, patients with and without AF were similar regarding body mass index, preoperative heart rate , time of ventilation in ICU, pump time, grafting or absence of grafting on right coronary artery (RCA) and the prevalence of chronic lung diseases, previous myocardial infarction, and diabetes mel- litus. Patients who developed AF had longer ICU stay (OR=4.92, P=0/000). Conclusion: The results of the present study demonstrated that the combination of congestive heart failure, and low left ventricular ejection fraction can identify patients at high risk for occurrence of AF after CABG.