Sex Differences in the Epidemiology of New-Onset In-Hospital Post–Coronary Artery Bypass Graft Surgery Atrial Fibrillation

New-onset atrial fibrillation (AF) after coronary artery bypass graft surgery (CABG) is associated with poorer long-term survival and increased morbidity. Because greater age is associated with higher risk of new-onset postCABG AF, the trend toward increasing age and risk profiles in the population of patients undergoing CABG makes understanding this common complication of cardiac surgery a high priority, so that effective means of prevention and management can be identified and developed. Because women undergoing CABG are typically older and have higher risk profiles than their male counterparts, such research may be particularly important to improving outcomes for women, even though some studies suggest that women have lower risk-adjusted odds of developing post-CABG AF. One study investigating the impact of post-CABG AF on long-term survival found that it affected women more significantly; another identified it as an independent risk factor for in-hospital mortality. Although previous studies have looked at the incidence of post-CABG AF in men and women—with some showing it to occur more frequently in women (although not to a statistically significant degree) and others showing similar rates or even lower risk for women—it is not known how patterns of type, timing, duration, or frequency compare between men and women. We collected detailed data on post-CABG AF events (detected via continuous in-hospital ECG/telemetry monitoring) that occurred in patients who underwent isolated CABG surgery at 4 large academic medical centers and 1 high-volume specialty cardiac hospital in the United States during a period of 9 years. Here, we describe and compare the Background—New-onset atrial fibrillation (AF) after coronary artery bypass graft surgery (CABG) is associated with increased morbidity and poorer long-term survival. Although many studies show differences in outcome in women versus men after CABG, little is known about the sex-specific incidence and characteristics of post-CABG AF. Methods and Results—Overall, 11 236 consecutive patients without preoperative AF underwent isolated CABG from 2002 to 2010 at 4 US academic medical centers and 1 high-volume specialty cardiac hospital. Data routinely collected for the Society of Thoracic Surgeons database were augmented with details on new-onset post-CABG AF events detected via continuous in-hospital ECG/telemetry monitoring. Unadjusted incidence of post-CABG AF was 29.5% (3312/11 236) overall, 30.2% (2485/8214) in men, and 27.4% (827/3022) in women. After adjustment for Society of Thoracic Surgeons–recognized risk factors, women had significantly lower risk for post-CABG AF (odds ratio [95% confidence interval]=0.75 [0.64–0.89]), shorter first, longest, and total duration of AF episodes (mean difference [95% confidence interval]=−2.7 [−4.7 to −0.8] hours; −4.1 [−6.9 to −1.2] hours; −2.4 [−2.5 to −2.3] hours, respectively). At 48 hours, AFfree probabilities were 77% for women and 72% for men (P<0.001). Number of episodes (P=0.18), operative mortality (P=0.048), stroke (P=0.126), and discharge in AF (P=0.234) did not differ significantly by sex. Conclusions—These novel data on sex-specific characteristics of new-onset AF after isolated CABG show that women had lower adjusted risk for post-CABG AF and experienced shorter episodes. Investigation of sex-specific impacts on outcomes is needed to identify optimal strategies for prevention and management to ensure all patients achieve the best possible outcomes. (Circ Cardiovasc Qual Outcomes. 2016;9:723-730. DOI: 10.1161/CIRCOUTCOMES.116.003023.)