Percent of heart failure patients with reduced ejection fraction < 40% on aldosterone antagonists. Aldosterone receptor antagonists (or mineralocorticoid receptor antagonists) are recommended in patients with NYHA class II-IV HF and who have LVEF of 40% or less, unless contraindicated, to reduce morbidity and mortality. Rate 1: Patient prescribed Aldosterone receptor antagonists (or mineralocorticoid receptor antagonists). Numerator note: Careful monitoring of potassium, renal function, and diuretic dosing should be performed at initiation and closely followed thereafter to minimize risk of hyper kalemia and renal insufficiency. (Level of Evidence: A). Rate 2: Patient using diuretics for symptom control