Beyond the Initial Insult: Clinical Characteristics and Prognosis of Heart Failure with Improved Ejection Fraction.

Introduction: Heart failure with improved ejection fraction (HFimpEF) is a recently defined subtype of HF, characterized by an increase in ejection fraction (EF) after a prior diagnosis of reduced EF. There are limited data on the characteristics and outcome of this patient subset. The study aimed to investigate the clinical profile and prognosis of this patient group.

Methods: HFimpEF patients from a large echocardiography database with comprehensive clinical and outcome data were evaluated for clinical characteristics and outcomes including mortality and cardiovascular hospitalizations. HFimpEF was defined as prior HF diagnosis with EF ≤40% followed by an EF increase of ≥10% to >40%.

Results: The study included 2,883 patients with an EF ≤40%. 27% (777) fulfilled criteria of HFimpEF. Non-ischemic cardiomyopathy, female sex, and smaller left ventricular dimensions were associated with EF improvement. Median follow-up duration was 1,346 days. Patients with HFimpEF had a significantly improved prognosis compared to those without EF improvement. Patients with a significant improvement in the EF (≥50%) experienced a 30% lower mortality rate (HR: 0.70, 95% CI: 0.57-0.86, p < 0.001) and a decreased risk of cardiovascular hospitalizations.

Conclusions: HFimpEF is a distinct clinical entity observed in 27% of patients with initially reduced EF and conveys a better prognosis. However, even with improvement, EF in most patients does not fully recover, and clinical events can still occur.