Aims The aim of this study is to investigate the prognostic implications
of the presence of heart failure (HF) across the range of left
ventricular ejection fraction (LVEF) in patients with comorbid atrial
fibrillation (AF).
Methods and results We conducted a retrospective cohort study of 1063
patients (median age 76 years), discharged from the cardiology ward with
a primary or secondary diagnosis of AF between 2015 and 2018. We used
Cox proportional-hazards and spline models to examine the association of
the presence of HF, across the range of LVEF, with the primary outcome
of all-cause mortality. HF was documented in 52.9% of patients at
baseline. During a median follow-up of 31 months (interquartile range 10
to 52 months), 37.3% of patients died. The presence of HF was
associated with a significantly higher risk of mortality [adjusted
hazard ratio (aHR) 2.17; 95% confidence interval (CI), 1.70 to 2.77; P
< 0.001], which was evident across HF with reduced (aHR 3.03; 95% CI
2.41 to 4.52), mid-range (aHR 2.08; 95% CI 1.47 to 2.94), and preserved
LVEF (aHR 1.94; 95% CI 1.47 to 2.55). Among patients with HF, the
spline curve depicted a non-linear association between LVEF and the risk
of death, in which there was a steep and progressive increase in
mortality for every 5% reduction in LVEF below 25% (aHR 1.97, 95% CI
1.04 to 3.73, P = 0.04).
Conclusions In patients with AF who were discharged from the hospital,
the presence of HF at baseline was independently associated with a
twofold risk of death, which was significant across LVEF-classified HF
subtypes. Among patients with AF and HF, the risk of death rose
significantly as LVEF was reduced below 25%