Background-Atrial fibrillation (AF) after coronary artery bypass graft surgery is a difficult problem and a continuing source of morbidity and mortality. However, the prognostic implications of postoperative AF are still in dispute. Our aim was to ascertain the impact of AF after coronary artery bypass graft on postoperative survival and to assess its prognostic role in cause-specific mortality. Methods and Results-We conducted a prospective observational study of 1832 patients undergoing isolated coronary artery bypass graft between January 2000 and December 2005 at 2 cardiac surgery centers in northern Italy. Patients affected by postoperative AF were identified and followed up until death or study end (April 30, 2007). A total of 570 patients (31%) developed AF after coronary surgery. Patients affected by postoperative AF experienced a longer hospital stay (7 days [25th to 75th percentile, 7 to 10 days] versus 7 days [25th to 75th percentile, 6 to 8 days]; PϽ0.001). Hospital mortality also was higher in AF patients (3.3% versus 0.5%; PϽ0.001). On discharge, 1806 patients were alive; 143 were lost to follow-up. The remaining 1663 were followed up for a median of 51 months (25th to 75th percentile, 41 to 63 months); 126 of them died after a median of 14 months (25th to 75th percentile, 5 to 32 months). Long-term mortality rates were significantly higher for patients with postoperative AF (2.99 per 100 person-years; 95% confidence interval, 2.33 to 3.84; 61 deaths) compared with those without the arrhythmia (1.34 per 100 person-years; 95% confidence interval, 1.05 to 1.71; 65 deaths), with an adjusted hazard ratio of 2.13 (PϽ0.001) and 2.56 (Pϭ0.001) when also accounting for the prescription of warfarin at discharge. With Cox regression, patients with AF were shown to be at higher risk of dying from embolism (adjusted hazard ratio, 4.33; 95% confidence interval, 1.78 to 10.52) but not from other causes. Conclusions-Postoperative AF affects early and late mortality after isolated coronary artery bypass graft surgery. Patients affected by AF are at higher risk of fatal embolic events. Careful postoperative surveillance with a specific antiarrhythmic and antithrombotic prophylaxis, aimed at reducing AF and its complications, is recommended.

BackgroundAtrial fibrillation (AF) remains the most common complication after cardiac surgery. The present study aim was to derive an effective bedside tool to predict postoperative AF and its related complications.Methods and ResultsData of 17 262 patients undergoing adult cardiac surgery were retrieved at 3 European university hospitals. A risk score for postoperative AF (POAF score) was derived and validated. In the overall series, 4561 patients (26.4%) developed postoperative AF. In the derivation cohort age, chronic obstructive pulmonary disease, emergency operation, preoperative intra‐aortic balloon pump, left ventricular ejection fraction <30%, estimated glomerular filtration rate <15 mL/min per m2 or dialysis, and any heart valve surgery were independent AF predictors. POAF score was calculated by summing weighting points for each independent AF predictor. According to the prediction model, the incidences of postoperative AF in the derivation cohort were 0, 11.1%; 1, 20.1%; 2, 28.7%; and ≥3, 40.9% (P<0.001), and in the validation cohort they were 0, 13.2%; 1, 19.5%; 2, 29.9%; and ≥3, 42.5% (P<0.001). Patients with a POAF score ≥3, compared with those without arrhythmia, revealed an increased risk of hospital mortality (5.5% versus 3.2%, P=0.001), death after the first postoperative day (5.1% versus 2.6%, P<0.001), cerebrovascular accident (7.8% versus 4.2%, P<0.001), acute kidney injury (15.1% versus 7.1%, P<0.001), renal replacement therapy (3.8% versus 1.4%, P<0.001), and length of hospital stay (mean 13.2 versus 10.2 days, P<0.001).ConclusionsThe POAF score is a simple, accurate bedside tool to predict postoperative AF and its related or accompanying complications.