Comparison of frequency of atrial fibrillation after coronary artery bypass grafting in African Americans versus European Americans.

In the general population, African Americans experience atrial fibrillation (AF) less frequently than European Americans. This difference could also exist in the incidence of this arrhythmia after cardiac surgery, but this possibility has been insufficiently examined. To test the association of such an ethnic difference, we compared the incidence of postoperative AF in a consecutive series of 2,312 African Americans and 6,054 European Americans who underwent isolated coronary artery bypass grafting from July 2000 to June 2007. Raw differences between the cohorts in the incidence of new AF were adjusted to take into account the baseline differences. Postoperatively, new-onset AF developed in 504 (22%) of 2,312 African-American patients and in 1,838 (30%) of 6,054 European-American patients (p <0.01). After adjustment with logistic regression analysis for numerous baseline differences, African Americans remained less likely to develop AF (odds ratio 0.63, 95% confidence interval 0.55 to 0.72; p <0.001). Risk was also adjusted using propensity matching. In that analysis, 457 (22%) of 2,059 African-American patients had postoperative AF, as did 597 (29%) of 2,059 matched European-American patients (p <0.01). In conclusion, AF was significantly less common among African-American patients than among European-American patients after coronary artery bypass grafting.