What ECG leads are associated with a lateral myocardial infarction?

What ECG leads are associated with a lateral myocardial infarction?

• A. I, aVL, V5, and V6
• B. II, III, aVF
• C. V1-V3
• D. aVR, V1

Answer: (A)

Lateral myocardial infarction shows ST-segment elevation in the lateral view of the heart, which are the leads that look at the outer left ventricle: I, aVL, V5, and V6. When the lateral wall is injured, the electrical current shifts in a way that elevates the ST segment in these leads. This pattern is typically due to occlusion of the left circumflex artery or its obtuse marginal branches. You may also see reciprocal ST depression in the inferior leads (II, III, aVF), which helps confirm a lateral territory involvement. This differs from inferior MI, which predominantly elevates in II, III, and aVF, and from anterior/septal MI, which elevates in V1–V4. aVR usually does not show primary elevations for a lateral MI and may reflect reciprocal changes instead.

Lateral myocardial infarction shows ST-segment elevation in the lateral view of the heart, which are the leads that look at the outer left ventricle: I, aVL, V5, and V6. When the lateral wall is injured, the electrical current shifts in a way that elevates the ST segment in these leads. This pattern is typically due to occlusion of the left circumflex artery or its obtuse marginal branches.

You may also see reciprocal ST depression in the inferior leads (II, III, aVF), which helps confirm a lateral territory involvement. This differs from inferior MI, which predominantly elevates in II, III, and aVF, and from anterior/septal MI, which elevates in V1–V4. aVR usually does not show primary elevations for a lateral MI and may reflect reciprocal changes instead.