Objective: This study aims to investigate the prevalence and prognostic value of right ventricular function in patients hospitalized due to heart failure with mildly reduced ejection fraction (HFmrEF). 

Background: Limited data regarding the prognostic impact of right ventricular function in patients with HFmrEF is available. 

Methods: A large retrospective registry was used including all consecutive hospitalized patients with HFmrEF (i.e., left ventricular ejection fraction (LVEF) 41 – 49%) from 2016 to 2022 according to current European guidelines. Longitudinal right ventricular function was assessed by measurements of TAPSE from standardized transthoratic echocardiography during clinical routine. The primary endpoint was the first heart-failure related re-hospitalization at 3 years. Secondary endpoints comprised amongst others in-hospital mortality. Kaplan-Meier, uni- and multivariable Cox regression analyses were applied for statistics.

Results: 695 consecutive patients with HFmrEF were included with completed right ventricular echocardiographic assessment. The prevalence of right heart failure defined as TAPSE < 18mm was 48%. HFmrEF patients with right heart failure were associated with an increased risk of heart-failure related re-hospitalization (13% vs. 8%; log rank p=0.040; HR= 1.678; 95% CI 1.018 - 2.766; p=0.042), even after multivariable adjustment (HR= 1.556; 95% CI 0.939 - 2.577; p=0.086; statistical trend). Accordingly, in-hospital mortality was higher in HFmrEF patients with right heart failure (8% vs. 2%; p=0.001). First cardiovascular re-hospitalization was not different.

Conclusions: Right heart failure in HFmrEF detiorates the prognosis with regard to in-hospital mortality and heart failure related re-hospitalization.