Heart Failure USMLE Step 1 Practice Question
A 72-year-old man with a 10-year history of hypertension presents with progressive dyspnea on exertion, orthopnea, and lower extremity edema. Physical examination reveals a laterally displaced point of maximal impulse, an S3 gallop, and crackles at both lung bases. Echocardiography shows a left ventricular ejection fraction of 32% with global hypokinesis. Which of the following pathophysiologic mechanisms most directly explains the development of his lower extremity edema?
Answer choices
- AIncreased sympathetic tone causing selective renal vasoconstriction
- BDecreased cardiac output causing reduced renal perfusion and sodium retentionCorrect answer
- CIncreased systemic vascular resistance leading to elevated afterload
- DPulmonary hypertension secondary to left-to-right shunting
- EImpaired lymphatic drainage from venous obstruction
- FF. Elevated aldosterone levels causing direct vasodilation of systemic arterioles
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