Serial echocardiography revealed that the EF of mice treated with the ERβ-agonist DPN significantly improved (from 33.2 ± 1.2% to 45.3 ± 2.1%, n = 7), while there was no improvement in the EF of HF mice treated with ERα-agonist PPT (from 33.0 ± 1.5% to 31.1 ± 2.3%, n = 6, Fig. 1). This evidence concerns the gene ESR2 and hydrops fetalis.