SLC8A1 and hydrops fetalis: This study demonstrated that 1) NRG-1β improves cardiac function of rats with volume-overload HF, 2) increases the Ca2+ current density of LV cardiomyocytes, and 3) promotes the expression levels of Ca2+ handling proteins, including Cav1.2, SERCA2a, and NCX1, in the LV tissue.