Heart Failure USMLE Step 1 Practice Question
A 22-year-old previously healthy student who has been studying all night stands up quickly and experiences brief dizziness. Vital signs show BP 92/58 mmHg, HR 118/min, RR 16/min, SpO2 98% on room air. He denies chest pain, dyspnea, and orthostatic symptoms persist only seconds. ECG shows normal sinus tachycardia. He takes no medications. Which of the following immediate physiologic response most likely restores blood pressure in this setting?
Answer choices
- AIncreased vagal output due to increased aortic arch stretch
- BIncreased atrial stretch causing reflex bradycardia
- CDecreased renin release from juxtaglomerular cells within seconds
- DIncreased carotid sinus firing leading to decreased sympathetic tone
- EDecreased baroreceptor firing leading to increased sympathetic outflowCorrect answer
- FIncreased aldosterone secretion leading to sodium and water reabsorption
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