Which finding on the ECG is most consistent with an anterior wall myocardial infarction?

• A. ST elevation in II, III, aVF
• B. ST depression in I and aVL
• C. ST elevation in V1 through V4
• D. ST elevation in aVR

Answer: (C)

This question tests how ECG leads map to heart wall areas and how ST elevations reflect a transmural infarct in a specific region. An anterior wall myocardial infarction is classically produced by occlusion of the left anterior descending artery, which supplies the anterior surface of the left ventricle. The ECG that best reflects this region shows ST elevation in the anterior chest leads V1 through V4, sometimes extending to V5-V6 if the infarct is larger. Those leads view the anterior wall directly, so their ST elevation indicates injury there.

The other patterns point to different regions or processes. ST elevations in the inferior leads (II, III, aVF) indicate an inferior wall MI, usually from RCA or sometimes LCx. ST depression in I and aVL can be the reciprocal changes seen with an inferior MI or indicate lateral ischemia, not the anterior wall. ST elevation in aVR is not a specific marker of an anterior wall MI; it can suggest diffuse subendocardial ischemia or left main/very proximal multivessel disease and is not the classic sign of anterior wall involvement.

So, ST elevation in the anterior chest leads V1 through V4 best fits an anterior wall myocardial infarction.