Clinical characteristics, predictors, and outcomes of heart failure with improved ejection fraction

Improvement in ejection fraction (EF) was observed in a subset of patients with heart failure (HF) and reduced ejection fraction (HFrEF). We analyzed and compared these patients with other HF phenotypes.Based on left ventricular ejection fraction(LVEF) at baseline and follow-up, the 561 HF patients were divided into 4 groups: HF preserved EF (HFpEF, LVEF ≥ 50% on both occasions, n = 258), HF mid-range EF (HFmrEF, fluctuating between LVEF 40 and 49% on both occasions, n = 61), HFrEF (LVEF < 40% on both occasions, n = 141), and HF improved EF (HFimpEF, defined as LVEF < 40% at baseline and LVEF ≥ 40% at follow-up with ≥10% absolute improvement, n = 101). The composite of HF readmission and all-cause mortality was considered the primary endpoint, and the secondary endpoint was all-cause mortality.The characteristics of HFimpEF differed from other HF phenotypes. β-blockers and aldosterone receptor antagonists were associated with improved LVEF. Kaplan-Meier curves showed the lowest incidence of the composite endpoint (p < 0.001) and all-cause mortality (p < 0.001) in HFimpEF. The risk of cardiovascular death was lowest in HFimpEF after controlling for competing events (p < 0.001), as were competing events (p < 0.001). Valvular heart disease (VHD) (HR 8.555, 95 CI% 2.126-34.420, p = 0.003) increased the risk of all-cause death, and anemia increased the risk of all-cause death (HR 5.533, 95 CI% 1.592-19.530, p = 0.007) and cardiovascular death in HFimpEF patients (HR 5.840, 95 CI% 1.088-31.356, p = 0.040).HFimpEF is an independent HF phenotype with a prognosis similar to HFmrEF and superior to HFpEF and HFrEF. When HFimpEF patients had VHD and anemia, the endpoint event rate was increased.