SLC5A2 and hydrops fetalis: The four pillars of treatment for HF with reduced ejection fraction (HFrEF) now include beta-blockers, mineralocorticoid receptor antagonists (MRAs), sodium-glucose cotransporter-2 inhibitors (SGLT2i), and either angiotensin-converting enzyme inhibitors (ACEi), angiotensin receptor–neprilysin inhibitors (ARNIs), or angiotensin receptor blockers (ARBs) [8].