Predictors of atrial fibrillation after coronary artery bypass surgery.

OBJECTIVE: Atrial fibrillation is one of the most common arrhythmias associated with not only increased morbidity after coronary artery bypass grafting but also increased healthcare costs. Many factors are associated with atrial fibrillation onset after coronary artery bypass grafting. We prospectively examined which factors could predict atrial fibrillation after coronary artery bypass grafting.

METHODS: Fifty-seven consecutive patients (37 men, mean age=60.2+/-12 years) with sinus rhythm before coronary artery bypass grafting are included the study. Clinical, demographic, laboratory and echocardiographic characteristics are all evaluated prospectively. The maximum and minimum P-wave duration (P(max) and P(min)) were measured from the 12-lead surface electrocardiogram. The difference between the P(max) and the P(min) was calculated and defined as P-wave dispersion. Preoperative venous blood samples were taken for N-terminal proBrain natriuretic peptide level analysis.

RESULTS: Ten (17%) patients had postoperative atrial fibrillation. Patients with postoperative atrial fibrillation were older (69.4+/-6 versus 58.2+/-12 years, P=0.01), had lower ejection fraction (44.1+/-8.9% versus 54.3+/-9; P=0.002), higher proBrain natriuretic peptide levels (538+/-136 pg/ml versus 293+/-359 pg/ml; P=0.03), longer P(max) (142.2+/-13.7 ms versus 120.8+/-21.2 ms; P=0.006) and longer P-wave dispersion (55.0+/-8.2 ms versus 41.3+/-14.3 ms; P=0.008) compared with the patients without atrial fibrillation. Univariate analysis showed that increased age (P=0.01), lower ejection fraction (P=0.02), enlargement of left atrium (P=0.02), increased P(max) (P=0.006) and increased P-wave dispersion (P=0.008) and increased level of preoperative proBrain natriuretic peptide (P=0.03) were associated with postoperative atrial fibrillation. Positive correlation was seen between the age and level of proBrain natriuretic peptide (r=0.322 and P=0.015). In multivariate analysis, age (P=0.05), lower ejection fraction (P=0.03), left atrial enlargement (P=0.05), longer P(max) (P=0.01) and P-wave dispersion (P=0.01) were found to be independent predictors of postoperative atrial fibrillation.

CONCLUSION: Age, poor left ventricular functions, P(max) and P-wave dispersion are found to be independent predictors of atrial fibrillation after coronary artery bypass grafting.