BACKGROUND

The revised universal definition of heart failure (HF) established a standardized definition for HF with improved ejection fraction (HFimpEF) and emphasized the importance of longitudinally assessing left ventricular EF (LVEF). We aim to investigate the incidence, disease progression, and clinical outcomes of HFimpEF in a longitudinal cohort of hospitalized HF patients.

METHODS

We retrospectively included HF patients with baseline LVEF ≤40 % and satisfactory echocardiographic follow-ups. HFimpEF was defined as a ≥ 10-point increase in LVEF to >40 %. Transient HFimpEF was defined as a recurrent LVEF ≤40 % after achieving HFimpEF. Clinical outcomes were all-cause death, cardiovascular death, and HF rehospitalization.

RESULTS

During a median follow-up of 47.9 months, 517 of 923 patients met HFimpEF criteria; 65.0 % HFimpEF cases occurred within 12 months. HFimpEF patients had lower risks of all-cause death (hazard ratio [HR] = 0.16, P < 0.001), cardiovascular death (HR = 0.19, P < 0.001), and HF rehospitalization (HR = 0.39, P < 0.001). However, 160 HFimpEF patients experienced LVEF worsening during follow-up; their risks for adverse events were higher (HR = 1.89 for all-cause death, HR = 2.13 for cardiovascular death, HR = 2.13 for HF rehospitalization, P < 0.05 for all) compared to persistent HFimpEF patients, and their capability of LVEF re-improvement was diminished. An inverted U-shaped LVEF profile for HFimpEF-characterized by a slow, modest increase followed by a decline-portended a higher mortality risk.

CONCLUSIONS

HFimpEF was observed in 56.0 % of HF patients. Longitudinally assessing LVEF helps identify HFimpEF patients and facilitates disease progression monitoring and risk stratification.