Inferior wall myocardial infarction is most commonly due to occlusion of which artery?

• A. Left Circumflex Artery
• B. Left Anterior Descending Artery
• C. Posterior Descending Artery
• D. Right Coronary Artery

Answer: (D)

Inferior wall ischemia is driven by the artery that mainly feeds the inferior portion of the left ventricle. In most people, that territory is supplied by the posterior descending artery, which typically arises from the right coronary artery. So when the right coronary artery becomes occluded, blood flow to the inferior wall is most often disrupted, leading to an inferior myocardial infarction.

There’s a caveat: in left-dominant circulations, the posterior descending artery comes from the left circumflex, so an RCA occlusion in those individuals might not cause an inferior MI as readily. Yet, across the population, occlusion of the right coronary artery remains the most common cause of inferior wall infarction. Clinically, this often presents with ST elevations in the inferior leads (II, III, aVF) and may be accompanied by signs of right ventricular involvement.