What is the role of ACE inhibitors in heart failure and what monitoring is essential?

• A. ACE inhibitors increase preload by expanding volume.
• B. ACE inhibitors reduce afterload and mortality; monitor renal function and potassium.
• C. ACE inhibitors primarily slow heart rate.
• D. ACE inhibitors are avoided in patients with heart failure.

Answer: (B)

ACE inhibitors act by blocking the formation of angiotensin II, which leads to arterial dilation (lower afterload) and reduced aldosterone-driven fluid retention. In heart failure, this combination improves symptoms, reduces hospitalizations, and lowers mortality, making them a foundational therapy for systolic heart failure.

Because these drugs affect kidney perfusion pressure and potassium handling, monitoring is essential. Check renal function (creatinine/eGFR) and potassium after starting therapy or after any dose change, and periodically thereafter. Early monitoring helps detect potential kidney function decline or hyperkalemia, especially in patients with preexisting kidney disease, dehydration, or concomitant potassium-sparing medications. They are not used to slow heart rate and are not avoided in heart failure; their mortality benefit is a key reason they are prescribed.