Contemporary data on the incidence and prognosis of heart failure (HF) and the influence of left ventricular ejection fraction (LVEF) in the setting of acute coronary syndrome (ACS) are scant. The aim of this study was to examine the relationship between LVEF and HF with long-term prognosis in a cohort of patients with ACS.

This is a retrospective observational study of 6208 patients consecutively admitted for ACS to 2 different Spanish hospitals. Baseline characteristics were examined and a follow-up period was established for registration of death and HF rehospitalization as the primary endpoint.

Among the study participants, 5064 had ACS without HF during hospitalization: 290 (5.8%) had LVEF<40%, 540 (10.6%) LVEF 40% to 49%, and 4234 (83.6%) LVEF ≥ 50%. The remaining 1144 patients developed HF in the acute phase: 395 (34.6%) had LVEF<40%, 251 (21.9%) LVEF 40% to 49%, and 498 (43.5%) LVEF ≥ 50%. Patients with LVEF 40% to 49% had a demographic and clinical profile with intermediate features between the LVEF <40% and LVEF ≥ 50% groups. Kaplan-Meier curves showed that mortality and HF readmissions were statistically different depending on LVEF in the non-HF group but not in the HF group. Left ventricular ejection fraction ≥ 50% was an independent prognostic factor in the non-HF group only.

In ACS, long-term prognosis is considerably worse in patients who develop HF during hospitalization than in patients without HF, irrespective of LVEF. This parameter is a strong prognostic predictor only in patients without HF.