Aims: Atrial fibrillation (AF)-associated poor outcomes in heart failure (HF) are often attributed to older age, advanced disease, and comorbidity burden of HF patients with AF. Therefore, we examined the effect of AF on outcomes in a propensity-matched study in which patients with and without AF were well balanced on all measured baseline characteristics. Methods and results: Of the 2708 advanced chronic systolic HF patients in the Beta-Blocker Evaluation of Survival Trial, 653 had a history of AF. Propensity scores for AF were calculated for each patient and were used to assemble a cohort of 487 pairs of patients with and without AF who were balanced on 74 baseline characteristics. Matched Cox regression analyses were used to estimate associations of AF with outcomes during 23 months of mean follow-up. All-cause mortality occurred in 187 (rate, 2046/10 000 person-years of follow-up) and 181 (rate, 1885/10 000 person-years) matched patients with and without AF, respectively [matched hazard ratio (HR) when AF was compared with no-AF 1.03, 95% confidence interval (CI) 0.79-1.33; P = 0.84]. Heart failure hospitalization occurred in 215 (rate, 3171/10 000 person-years) and 184 (rate, 2405/10 000 person-years) matched patients with and without AF, respectively (matched HR when AF was compared with no-AF 1.28, 95% CI 1.00-1.63; P = 0.049). Hazard ratios and 95% CIs for AF-associated HF hospitalization for bucindolol and placebo groups were, respectively, 1.08 (0.81-1.43) and 1.54 (1.17-2.03; P for interaction = 0.09). Conclusion: A history of AF had no intrinsic association with mortality but was associated with HF hospitalization in chronic systolic HF. © The Author 2009.