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: C

Rationale: The correct answer is C: Reduction of preload and afterload. Captopril, an ACE inhibitor, reduces preload (volume of blood returning to the heart) by inhibiting the conversion of angiotensin I to angiotensin II, which decreases aldosterone secretion and fluid retention. It also reduces afterload (resistance the heart has to pump against) by decreasing peripheral vascular resistance. This dual action helps improve cardiac output and decrease workload on the heart in systolic heart failure. Explanation for why the other choices are incorrect: A: Increased cardiac contractility - Captopril does not directly increase cardiac contractility, it mainly affects afterload and preload. B: Reduction of angiotensin-mediated vasoconstriction in the kidney - While captopril does inhibit angiotensin production, its primary mechanism of action is not specific to the kidney. D: Stimulation of epinephrine release from adrenergic nerves - Captopril does not stimulate ep

Correct Answer: A

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

Correct Answer: D

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: D

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