Which leads are primarily affected by an inferior wall myocardial infarction?

Which leads are primarily affected by an inferior wall myocardial infarction?

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

Answer: (C)

Inferior wall myocardial infarction primarily affects the leads that look at the inferior surface of the heart, which are leads II, III, and aVF. These leads are positioned in such a way that they capture electrical activity from the inferior wall, which is supplied by the right coronary artery in a majority of right-dominant hearts.

When there is an obstruction in blood flow to this area, typically evidenced by ST-segment elevation in these leads, it indicates that the myocardium is not receiving adequate oxygen, leading to infarction. Conversely, the other leads mentioned—V1, V2, I, aVL, V5, and V6—focus on other areas of the heart: V1 and V2 are more related to the anterior and septal regions, while I and aVL inspect the lateral wall. V5 and V6 monitor the lateral and left inferior aspect of the heart. Thus, it is leads II, III, and aVF that most directly reflect the changes associated with inferior wall myocardial infarction, making these the correct choice.