ST elevations in leads II, III, and aVF indicate infarction in which territory and artery?

ST elevations in leads II, III, and aVF indicate infarction in which territory and artery?

• A. Inferior MI; Right coronary artery
• B. Anterior MI; Left anterior descending
• C. Lateral MI; Left circumflex
• D. Posterior MI; Posterior descending artery

Answer: (A)

ST elevations in leads II, III, and aVF point to an infarction of the heart’s inferior wall. The inferior surface is supplied most commonly by the right coronary artery, especially in the usual right-dominant circulation. When the RCA becomes occluded, the inferior portion of the left ventricle experiences transmural ischemia, which manifests on the ECG as ST elevations in those inferior leads. If the infarction were in the anterior wall, you’d expect ST elevations in the chest leads over the anterior surface (V1–V4). Lateral infarction would show changes in leads I, aVL, and often V5–V6. Posterior infarction typically presents with ST depressions in the anterior leads (V1–V3) or requires posterior leads to confirm. Thus, the pattern described best matches an inferior myocardial infarction due to RCA occlusion.

ST elevations in leads II, III, and aVF point to an infarction of the heart’s inferior wall. The inferior surface is supplied most commonly by the right coronary artery, especially in the usual right-dominant circulation. When the RCA becomes occluded, the inferior portion of the left ventricle experiences transmural ischemia, which manifests on the ECG as ST elevations in those inferior leads.

If the infarction were in the anterior wall, you’d expect ST elevations in the chest leads over the anterior surface (V1–V4). Lateral infarction would show changes in leads I, aVL, and often V5–V6. Posterior infarction typically presents with ST depressions in the anterior leads (V1–V3) or requires posterior leads to confirm. Thus, the pattern described best matches an inferior myocardial infarction due to RCA occlusion.