Which ECG leads are most informative for detecting inferior myocardial infarction?

• A. II, III, aVF
• B. aVR, V1, V2
• C. I, II, III
• D. V5, V6, I

Answer: (A)

Detecting inferior myocardial infarction relies on the ECG leads that best visualize the heart’s inferior wall. The inferior wall is captured most effectively by the limb leads II, III, and aVF, since they view the heart from below and align with the direction of injury current when the inferior region is affected (often due to RCA occlusion). ST elevation in these three leads is the most sensitive pattern for an inferior MI, and seeing concordant elevations across them strengthens the diagnosis.

The other leads look at different regions: aVR tends to show reciprocal changes rather than the primary ST elevations for inferior injury; anterior and septal leads (V1–V2) assess the front of the heart, not the inferior wall; and lateral leads (I, V5–V6) visualize the lateral surface. Because they don’t primarily reflect the inferior wall, they’re less informative for this specific infarct pattern.