Coronary Artery Disease USMLE Step 1 Practice Question
A 72-year-old man with chronic uncontrolled hypertension (BP 168/98 mmHg, HR 88/min, RR 16/min) presents with exertional chest discomfort. Physical examination reveals a prominent S4 gallop. Recent troponin is negative, but electrocardiography shows left ventricular hypertrophy with strain pattern. He denies orthopnea and has no lower extremity edema. He takes lisinopril irregularly. Which of the following best explains the origin of this S4 gallop?
Answer choices
- ARapid passive filling into a volume overloaded ventricle
- BBackflow across a stenotic aortic valve
- COscillation of the pericardium during inspiration
- DClosure of the mitral and tricuspid valves
- EAtrial contraction into a stiff noncompliant ventricleCorrect answer
- FPremature closure of the aortic valve due to elevated left ventricular pressures
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.