Myocardial Infarction — ORE Part 1 MCQ

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ModeratePharmacology & TherapeuticsMyocardial InfarctionORE Part 1

A patient in the dental chair develops central chest pain radiating to the left arm. They are conscious, pale, and sweating. Glyceryl trinitrate (GTN) has been administered sublingually without relief after 5 minutes. What is the most appropriate next step?

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Correct answer: D — Call 999 and administer aspirin 300 mg orally (chewed or dispersed)

When chest pain persists 5 minutes after GTN administration despite clinical features of acute coronary syndrome (central chest pain radiating to left arm, diaphoresis, pallor), acute myocardial infarction must be suspected. UK emergency guidance is clear: call 999 for ambulance transfer and administer aspirin 300 mg orally (chewed, not swallowed whole) unless contraindicated by allergy, active peptic ulcer, or bleeding disorder. Aspirin irreversibly inhibits platelet aggregation and reduces mortality and recurrent events in acute coronary syndromes. Option E (second GTN) delays emergency care inappropriately; GTN failure after first dose indicates need for hospital reperfusion therapy. Option C (intramuscular adrenaline) is reserved for anaphylaxis, not ACS. Option A (high-flow oxygen) is not first-line in secondary/emergency care; oxygen titration by SpO₂ target is standard. Option B contradicts NHS guidance, which recommends upright supported positioning to reduce cardiac workload.

Reference: NHS (2024–2026) Symptoms of a heart attack and Heart attack emergency care. https://www.nhs.uk/conditions/heart-attack/ Corroborated by Scottish NHS Emergency Department Chest Pain Guidelines (CEM SCOT, September 2023).