Increased preoperative white blood cell count predicts postoperative atrial fibrillation after coronary artery bypass surgery.

Objective: To better understand the relationship between humoral and cellular markers of inflammation and postoperative atrial fibrillation (AF).

Design: A prospective and descriptive study.

Setting: Academic institution.

Participants: Sixty adult patients > or = 60 years of age presenting for elective coronary artery bypass surgery with cardiopulmonary bypass (CPB).

Interventions: None.

Measurements And Main Results: With institutional review board approval, serial measurements for high sensitivity C-reactive protein (CRP) and white blood cell count (WBC) were performed before the induction of anesthesia, on arrival in the intensive care unit, and on the mornings of postoperative days 1 and 2. Continuous telemetry and daily 12-lead electrocardiographs were used to confirm new-onset AF. AF occurred in 17 of 60 (28%; 95% confidence interval, 17%-41%) patients. A history of preoperative myocardial infarction was more frequent among patients who developed AF (p = 0.049). Patients with or without AF did not differ in CRP values at any of the 4 study time points (p = 0.61 to p = 0.81). Preoperative WBC values were higher for patients who developed AF, and, according to stepwise logistic regression, it was the sole independent predictor of postoperative AF (odds ratio = 6.7; 95% confidence interval, 1.6-29.0; p = 0.01). A 2-fold higher preoperative WBC was associated with a nearly 7-fold higher risk of developing AF, and WBC >7 x 10(9)/L was associated with a nearly 4-fold higher risk of AF (odds ratio = 3.8, p = 0.03).

Conclusion: In this cohort of patients undergoing CABG surgery, preoperative leukocytosis was a significant predictor of AF independent of CRP.