AbstractAimsThis study aimed to investigate the prognostic value of dynamic changes in left ventricular ejection fraction (EF) for cardiovascular (CV) outcomes in an all‐comer heart failure (HF) population with reduced EF (HFrEF, EF < 40%). We sought to identify independent factors related to improvement in EF and to identify risk factors for increased risk of CV events in the subgroups of improved EF (iEF) and non‐improved EF (niEF), respecively.Methods and resultsThis is a retrospective sub‐analysis from the REDEAL HF trial, which included consecutive patients with chronic HF who were hospitalized from July 2009 to December 2017. Baseline and follow‐up echocardiography data (interval ≥12 months) of 573 consecutive patients with HFrEF were analysed. iEF was defined as absolute improvement in EF ≥ 10% and follow‐up EF over 40%. The primary endpoint was defined as a composite endpoint of cardiovascular (CV) death, CV hospitalization, or appropriate implantable cardioverter‐defibrillator (ICD) therapy for ventricular arrhythmia. EF improved in 37.2% of patients with HFrEF during follow‐up (median period of 17 months). iEF was independently associated with shorter HF duration (>4 vs. ≤4 years, odd ratio [OR] = 0.477, 95% CI 0.305–0.745), no coronary artery disease (CAD vs. no CAD, OR = 0.583, 95% CI 0.396–0.858), and no ICD implantation (ICD vs. no ICD, OR = 0.341, 95% CI 0.228–0.511). Compared with niEF, iEF was significantly and independently associated with lower all‐cause mortality (22.1% vs. 31.1%, P = 0.019; hazard ratio [HR] = 0.674, 95% CI 0.469–0.968), lower CV mortality (8.9% vs. 16.1%, P = 0.015; HR = 0.539, 95% CI 0.317–0.916), and lower CV events risk (27.2% vs. 49.2%, P < 0.001; HR 0.519, 95% CI 0.381–0.708), after adjustment for age, sex, duration of HF, and other clinical risk factors. Hypertension (HR = 2.452, P = 0.032) and elevated N‐terminal prohormone of brain natriuretic peptide (NT‐proBNP >1153 pg/mL, HR = 4.372, P < 0.001) were identified as independent risk factors for CV events in the iEF subgroup. ICD implantation (HR = 1.533, P = 0.011), elevated NT‐proBNP (HR = 1.626, P = 0.018), increased left atrial volume index (HR = 1.461, P = 0.021), reduced lateral mitral annular plane systolic excursion (HR = 1.478, P = 0.025), and reduced tricuspid plane systolic excursion (HR = 1.491, P = 0.039) were identified as risk factors for CV events in the niEF subgroup.ConclusionsImprovement in EF is independently related to the longer survival and lower CV related mortality and hospitalization rate of HFrEF. Elevated baseline NT‐proBNP is identified as the strongest prognostic factor associated with increased CV events risk in HFrEF patients both with and without improved EF, regardless of age, sex, duration of HF, and other clinical risk factors.