The impact of postoperative atrial fibrillation on neurocognitive outcome after coronary artery bypass graft surgery

Neurocognitive decline is a continuing source of morbidity after cardiac surgery. Atrial fibrillation occurs often after cardiac surgery and has been linked to adverse neurologic events. We sought to determine whether postoperative atrial fibrillation was associated with postoperative cognitive dysfunction. Four-hundred-eleven patients were enrolled to receive a battery of neurocognitive tests both preoperatively and 6 wk after elective coronary artery bypass graft surgery. Neurocognitive test scores were separated into four cognitive domains, with a composite cognitive index (the mean of the four domain scores) determined for each patient at every testing period. Multivariable analysis controlling for age, years of education, diabetes mellitus, left ventricular ejection fraction, and preoperative atrial fibrillation compared the presence of postoperative atrial fibrillation with change in cognitive function. Three-hundred-eight patients completed both pre- and postoperative cognitive testing; 69 patients (22%) had postoperative atrial fibrillation. Those who developed atrial fibrillation showed more cognitive decline than those who did not develop postoperative atrial fibrillation (P = 0.036). Atrial fibrillation was associated with poorer cognitive function 6 wk after surgery. Although the mechanism of this association is yet to be determined, prevention of atrial fibrillation may result in improved neurocognitive function.