What best describes the therapeutic effect of ACE inhibitors in heart failure?

• A. ACE inhibitors primarily improve preload
• B. ACE inhibitors reduce afterload and mortality; monitor renal function and potassium
• C. ACE inhibitors have no role in HF
• D. ACE inhibitors worsen potassium levels

Answer: (B)

ACE inhibitors in heart failure work by blocking the RAAS, which reduces angiotensin II–mediated vasoconstriction and aldosterone-driven sodium and water retention. This leads to vasodilation and a drop in afterload, making it easier for the heart to eject blood and improving forward flow. Over time, this neurohormonal modulation also slows adverse remodeling and lowers mortality in patients with reduced ejection fraction HF.

The reason this option is the best is that it captures both the hemodynamic effect (reduced afterload) and the important clinical outcome (reduced mortality), along with a crucial safety consideration: renal function and potassium need to be monitored because ACE inhibitors can raise creatinine and potassium levels. This combination reflects both efficacy and real-world management.

The other statements don’t fit as well. ACE inhibitors do have a role in heart failure, not none. Their main action is afterload reduction rather than preload, though venodilation can modestly affect preload but is not the primary effect. While they can raise potassium, saying they always worsen potassium is an oversimplification; monitoring is essential to manage this risk, rather than assuming a universal worsening.