Atrial fibrillation after beating heart CABG surgery: 019
Introduction: Atrial fibrillation (AF) is the most common complication after coronary artery bypass grafting surgery. Older age is the only variable consistently associated with the development of postoperative atrial fibrillation. The purpose of this study was to identify perioperative characteristics associated with new-onset atrial fibrillation in patients undergoing isolated off pump (OP) coronary artery bypass grafting.
Method: Data of 382 consecutive elective CABG who had complete revascularization with the OP-technique and who had no history of AF, have been prospectively collected (April 2001-December 2002). Standard anaesthesia was followed by an overnight ICU stay. Postoperative AF occurrence requiring oral or intravenous drug treatment or cardioversion for rate control was followed up until discharge from the hospital. Data were analysed with the SAS statistical software package for multivariate stepwise forward analysis.
Results: AF was recorded in 84/382 patients (22%), 5 of them were discharged in AF. By univariate analysis the patients who developed AF differed from those who did not by the following variables: age (68 ± 9.1 vs. 64 ± 9.4 P = 0.01); preoperative renal impairment defined as creatinine >120 μmol/L (25% vs. 12% P = 0.006); re-intervention (8.3% vs. 3.4% P = 0.05); revascularization of the diagonal branch (32% vs. 22% P = 0.05); use of postoperative epinephrine (8.3% vs. 1.7% P = 0.006). Patients who developed atrial fibrillation had a prolonged hospital stay (7 ± 3.4 vs. 6 ± 3.6 days, P = 0.03). Overall mortality was 0.5% (2 patients who had no AF). Stroke was recorded in 2 patients (one who had developed AF and one in the non-AF group). On a multivariate analysis the predictors of AF were the following: age (OR 1.04 per year; 95% CI 1.01-1.07 P = 0.004); preoperative renal impairment (OR 1.9; 95% CI 1.04-3.7 P = 0.04); postoperative epinephrine infusion (OR 4.0; 95% CI 1.2-13.5 P = 0.02).
Discussion: This study confirms that the incidence of post-operative AF after CABG is still high even when the OP-technique is used, occurring in 22% of our patients. Even when AF is uncomplicated, its treatment requires additional medical and nursing time and a prolonged hospitalization (7 ± 3.4 vs. 6 ± 3.6days in our experience P = 0.03). There is no explanation for some patients developing postoperative AF whereas others, having the same surgical intervention, remain in sinus rhythm. The present study confirms the association of AF with increasing age, explained by the age-related structural changes in the atrium such as dilatation, muscle atrophy, decreased conduction tissue and fibrosis. In our study AF is also predicted by preoperative renal impairment and postoperative epinephrine infusion.© 2004 European Society of Anaesthesiology