Vascular Disease USMLE Step 1 Practice Question
A 58-year-old man with a history of atrial fibrillation not on anticoagulation presents with acute left leg pain, coolness, and pallor. Vital signs show HR 118 bpm, BP 142/88 mmHg, RR 20, temp 37.2°C. Physical exam reveals absent left femoral pulse and mottled skin; right leg pulses remain intact. ECG confirms atrial fibrillation with rapid ventricular response. Doppler ultrasound shows no atherosclerotic plaque in the aorta. Which of the following is the most likely source of embolism?
Answer choices
- ALeft atrial thrombus from atrial fibrillationCorrect answer
- BVenous thrombosis from prolonged immobility
- CRuptured atherosclerotic plaque in the aorta
- DLeft ventricular thrombus from prior myocardial infarction
- EParadoxical embolism through a patent foramen ovale
- FThrombosis of the left iliac artery from atherosclerotic disease
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