Cardiovascular Drugs USMLE Step 1 Practice Question
A 71-year-old man with hypertension and type 2 diabetes presents to the emergency department with inferior ST-elevation myocardial infarction (STEMI). His vital signs on arrival are: blood pressure 148/92 mmHg, heart rate 88 bpm, respiratory rate 16/min. ECG shows ST elevations in leads II, III, and aVF with reciprocal changes. Troponin I is 4.2 ng/mL. After initiation of dual antiplatelet therapy and emergent cardiac catheterization, the patient develops severe bradycardia (heart rate 38 bpm), hypotension (82/54 mmHg), and second-degree atrioventricular block on repeat ECG. The patient was given intravenous metoprolol 5 mg Ć 3 doses prior to this complication. Which of the following beta-blockers would have posed the LOWEST risk of precipitating conduction system abnormalities in the acute phase of inferior STEMI?
Answer choices
- AEsmololāultra-short-acting, beta-1 selective with rapid reversibilityCorrect answer
- BMetoprololābeta-1 selective with moderate duration of action
- CPropranololānon-selective with membrane-stabilizing properties
- DSotalolānon-selective with Class III antiarrhythmic activity
- ECarvedilolānon-selective with alpha-blocking and vasodilatory effects
- FLabetalolācombined alpha and beta-blocker with extended half-life
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations ā plus adaptive practice that targets your weak areas ā with a free MedBoardPRO account.