Tachyarrhythmias and triggering factors for atrial fibrillation after coronary artery bypass operations

Background. We evaluated the role of supraventricular arrhythmias and assessed clinical predictors of atrial fibrillation (AF) that developed after coronary artery bypass operations. Methods. Eighty patients, with a mean age of 65.8 years, underwent 24-hour Holter monitoring preoperatively and for 4 consecutive days postoperatively, or until clinically documented AF, for analysis of the number of premature beats and tachyarrhythmias. Atrial areas and atrial peptides were measured preoperatively and postoperatively. Results. Twenty-nine of 80 (36.3%) patients had postoperative AF. Preoperatively, the maximal supraventricular premature beats per minute were higher in the AF group (p = 0.02). The body mass index and total amount of cardioplegia were lower (p = 0.02 and p = 0.006, respectively), and withdrawal of P-blockers postoperatively more frequent (p = 0.001) in the AF group, but atrial areas and atrial peptides did not differ. Conclusions. Frequent supraventricular premature beats preoperatively may indicate a propensity for AF. A larger amount of cardioplegia during the cross-clamp period may reduce the risk of postoperative AF. Further studies are mandatory to clarify why patients with lower body mass index were more prone to AF. (C) 2000 by The Society of Thoracic Surgeons.