ACC, American College of Cardiology; ACEi, angiotensin-converting enzyme inhibitor; AHA, American Heart Association; ARB, angiotensin receptor blocker; COR, class of recommendation; ESC, European Society of Cardiology; HF, heart failure; HFrEF, heart failure with reduced ejection fraction; LOE, level of evidence; NYHA, New York Heart Association. Here, ACE is linked to hydrops fetalis.