skip to main content

Atrial fibrillation stroke prevention — ABIM Board MCQ

Instant feedback + full explanation. One question, done properly.

ModerateCardiovascularAtrial fibrillation stroke preventionABIM Board

A 62-year-old woman with hypertension and diabetes mellitus presents with palpitations. ECG shows atrial fibrillation with a ventricular rate of 118/min. She has no heart failure, prior stroke or transient ischemic attack, vascular disease, mechanical heart valve, or moderate-to-severe rheumatic mitral stenosis. Serum creatinine is 0.9 mg/dL, hemoglobin is 13.1 g/dL, and there is no active bleeding. Her ventricular rate improves after metoprolol. Which of the following is the most appropriate long-term therapy for stroke prevention?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: B — Oral anticoagulation with a direct factor Xa inhibitor

The correct answer is B. Her CHA2DS2-VASc score is 3: hypertension, diabetes mellitus, and female sex each contribute 1 point; age 62 contributes no point. This corresponds to a guideline-level indication for long-term oral anticoagulation. Because she has no mechanical heart valve or moderate-to-severe rheumatic mitral stenosis and has preserved renal function, a direct oral anticoagulant such as a factor Xa inhibitor is preferred over warfarin. Aspirin and dual antiplatelet therapy provide inadequate stroke prevention, and the 2023 ACC/AHA/ACCP/HRS guideline explicitly states they are not recommended as alternatives to anticoagulation. Anticoagulation is based on thromboembolic risk, not solely on whether cardioversion is planned. If warfarin were required, the usual target INR would be 2.0 to 3.0, not 3.0 to 4.0.

Reference: Joglar JA, Chung MK, Armbruster AL, et al. 2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation (Antithrombotic Therapy recommendations), summarized in ACC Key Perspectives, Nov 2023. https://www.acc.org/latest-in-cardiology/ten-points-to-remember/2023/11/27/19/46/2023-acc-guideline-for-af-gl-af