A 68-year-old man was diagnosed with systolic heart failure with normal ejection fraction and normal sinus rhythm at rest. A treatment with captopril was started. Which of the following actions most likely mediated the therapeutic effect of captopril in this patient?

Correct Answer: B

Rationale: The correct answer is B: Reduction of angiotensin-mediated vasoconstriction in the kidney. Captopril is an ACE inhibitor that works by blocking the conversion of angiotensin I to angiotensin II. In this patient with systolic heart failure, reducing angiotensin II levels will lead to vasodilation and decreased vasoconstriction in the kidney, improving renal blood flow and reducing fluid retention. This helps to alleviate symptoms of heart failure and improve overall cardiac function. Incorrect choices: A: Increased cardiac contractility - Captopril does not directly increase cardiac contractility. C: Reduction of preload and afterload - While ACE inhibitors can reduce preload and afterload, the primary mechanism of captopril is through the renin-angiotensin-aldosterone system. D: Stimulation of epinephrine release from adrenergic nerves - Captopril does not stimulate epinephrine release; it actually inhibits the

Correct Answer: C

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: C

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: C

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: C

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.