ACE and heart failure: CIBIS II: "Cardiac Insufficiency Bisoprolol Study II"; MERIT-HF: Metoprolol CR/XL Randomized Intervention Trial in Congestive Heart Failure; COPERNICUS: "Effects of carvedilol on the morbidity of patients with Severe and Chronic Heart Failure"; EF: Ejection fraction; NYHA: "New York Heart Association"; HF: Heart failure; ACEI: Angiotensin-converting enzyme inhibitor; mg: milligram; CR: Controlled release; XL: Extended-release; BB: Beta-blocker