Frequency, predictors, and prognosis of heart failure with improved left ventricular ejection fraction: a single-centre retrospective observational cohort study

Aims An improved left ventricular ejection fraction (HFiEF) was observed across heart failure (HF) patients with a reduced or mid-range ejection fraction (HFrEF or HFmrEF, respectively). We postulated that HFiEF patients are clinically distinct from non-HFiEF patients. Methods and results A total of 447 patients hospitalized due to a clinical diagnosis of HF (LVEF <50% at baseline) were enrolled from September 2017 to September 2019. Echocardiogram re-evaluation was conducted repeatedly over 6 months of follow-up after discharge. The primary endpoint included the composite of HF hospitalization and all-cause mortality. Subjects (n = 184) with HFiEF (defined as an absolute LVEF improvement >= 10%) were compared with 263 non-HFiEF (defined by <10% improvement in LVEF) subjects. Multivariable Cox regression was performed and identified younger age, smaller left ventricular end diastolic dimension (LVEDD), beta-blocker use, AF ablation and cardiac resynchronization therapy (CRT) as independent predictors of HFiEF. According to Kaplan-Meier analysis, HFiEF subjects had lower cardiac composite outcomes (P = 0.002) and all-cause mortality (P = 0.003) than non-HFiEF subjects. Multivariate Cox survival analysis revealed that non-HFiEF (compared with HFiEF) was an independent predictor of both the primary endpoints (HR = 0.679, 95% CI: 0.451-0.907, P = 0.012), which was driven by all-cause mortality (HR = 0.504, 95% CI: 0.256-0.991, P = 0.047). Conclusions These data confirm that compared with non-HFiEF, HFiEF is a distinct HF phenotype with favourable clinical outcomes.