Τhe association of heart failure across left ventricular ejection fraction with mortality in atrial fibrillation

Abstract

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%.

Keywords: Atrial fibrillation; Death; Ejection fraction; Heart failure; Hospitalization; Mortality.

Figure 1

Cumulative incidence of outcomes according to presence of HF at baseline. aHR, adjusted hazard ratio; AF, atrial fibrillation; CI, confidence interval; CV, cardiovascular; HF, heart failure.

Figure 2

Type of HF at baseline compared with patients without HF: adjusted HRs of outcomes. Hazard ratios of outcomes by type of HF, using no HF as reference. HRs with 95% confidence intervals were calculated using Cox models, adjusted for intervention/control group assignment, age, sex, AF type, the presence or absence of chronic coronary syndrome, diabetes, hypertension, and the levels of N‐terminal pro‐BNP, high‐sensitivity cardiac troponin T and estimated glomerular filtration rate. AF, atrial fibrillation; CI, confidence interval; CV, cardiovascular; HF, heart failure; HR, hazard ratio; HFrEF heart failure with reduced ejection fraction; HFmrEF heart failure with mid‐range ejection fraction; HFpEF heart failure with preserved ejection fraction.

Figure 3

Adjusted association between LVEF and outcomes. Spline curves of outcomes of AF‐HF patients over a median 2 year follow‐up. The associations of LVEF with (A) all‐cause mortality and (B) the composite of CV death and all‐cause hospitalization are shown. Dashed lines represent 95% confidence intervals. The colour scale corresponds to the different HF subtypes (red, HFrEF; yellow, HFmrEF; & green, HFpEF). The models were adjusted for: intervention/control group assignment, age, sex, AF type, the presence or absence of chronic coronary syndrome, diabetes, hypertension, the use or non‐use of a beta‐blocker, angiotensin‐converting–enzyme inhibitor, mineralocorticoid‐receptor antagonist, oral anticoagulation, and the levels of N‐terminal pro‐BNP, high‐sensitivity cardiac troponin T, and estimated glomerular filtration rate. AF, atrial fibrillation; CV; cardiovascular; LVEF, left ventricular ejection fraction; HF, heart failure; HFrEF heart failure with reduced ejection fraction; HFmrEF heart failure with mid‐range ejection fraction; HFpEF heart failure with preserved ejection fraction; HR, hazard ratio.