How do ACE inhibitors improve outcomes in heart failure?

• A. They increase heart rate
• B. They dilate efferent arterioles, reduce afterload, decrease aldosterone, decrease remodeling and progression of HF
• C. They increase contractility
• D. They cause vasoconstriction to maintain BP

Answer: (B)

ACE inhibitors work by blocking the angiotensin-converting enzyme, which lowers angiotensin II levels. With less angiotensin II, blood vessels dilate, especially the efferent arterioles in the kidneys, which reduces afterload and improves forward flow. They also decrease aldosterone secretion, reducing sodium and water retention and thus lowering preload and edema. In heart failure, angiotensin II and aldosterone contribute to adverse remodeling of the heart—fibrosis and hypertrophy that worsen function. By dampening these signals, ACE inhibitors slow or reverse remodeling, improving ventricular performance and survival. They do not raise heart rate or contractility, and they promote vasodilation rather than vasoconstriction, fitting the improved hemodynamics seen in heart failure.