A 62-year-old man presents with crushing chest pain. ECG shows ST elevation in leads II, III and aVF with reciprocal depression in lead I. Coronary angiography demonstrates total occlusion of a single vessel. Which artery is most likely involved?
- A Left anterior descending artery
- B Left main coronary artery
- C Right coronary artery ✓
- D Left circumflex artery
Correct answer: C. Right coronary artery
Explanation
Leads II, III and aVF face the inferior surface of the heart, which is supplied by the right coronary artery through its posterior descending branch in about 85 percent of people (right dominant circulation). Occlusion there produces inferior infarction, often with sinus bradycardia or atrioventricular block because the RCA supplies the SA and AV nodes more often than any other vessel. The LAD supplies the anterior wall and apex (V1 to V4 changes), while the circumflex supplies the lateral wall.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
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