EFNB1 and heart failure: In line with this assumption, a recent RNAseq study performed on ventricles from HFpEF, heart failure with reduced ejection fraction (HFrEF), and control patients reported a specific and more significant downregulation of the Efnb1 gene in HFpEF than HFrEF patients (p=9.10–14 HFpEF vs. control, p=2.10–5 HFrEF vs. control, p=0.005 HFpEF versus HFrEF) (Hahn et al., 2021).