With regard to HF treatments, European guidelines recommend the use of renin–angiotensin system inhibitors (preferably sacubitril/valsartan), beta-blockers, SGLT2is, and mineralocorticoid receptor antagonists as first-line therapies for patients with HFrEF (and with a lower strength of evidence for patients with HFmrEF). This evidence concerns the gene REN and hydrops fetalis.