The importance of age as a predictor of atrial fibrillation and flutter after coronary artery bypass grafting.

The purpose of this study was to identify factors associated with atrial fibrillation and flutter after coronary artery bypass grafting. The study group consisted of a consecutive series of 5807 patients who underwent coronary artery bypass grafting alone and who were in sinus rhythm preoperatively. Atrial fibrillation and flutter were identified during continuous monitoring or by clinical symptoms and signs; they occurred in 17.2% of the patients. The prevalence of atrial fibrillation and flutter was directly related to age at operation, varying from 3.7% in patients aged less than 40 years to 27.7% in patients aged 70 and over. In a multivariate analysis, age remained the most important independent predictor of atrial fibrillation and flutter (p less than 0.001). Other independent predictors of atrial fibrillation and flutter were chronic airflow limitation (p = 0.006), preoperative beta-adrenergic blockers (p = 0.011), and chronic renal failure (p = 0.04). Extent of coronary disease at catheterization, history of a previous myocardial infarction, heart size on chest x-ray film, and all operative factors measured, apart from year of operation, were unassociated with atrial fibrillation and flutter. Thus atrial arrhythmias after coronary artery bypass operations are most strongly related to advanced age and are unassociated with preoperative left ventricular function and extent of coronary disease.