Which posterior leads may show ST elevations in posterior MI?

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Multiple Choice

Which posterior leads may show ST elevations in posterior MI?

Posterior MI involves the back wall of the left ventricle, and the electrical changes are best seen on leads that view the posterior surface. To detect this, we place posterior leads on the back that correspond to the same horizontal positions as the chest leads: V7, V8, and V9. In a posterior infarction, these leads show ST elevations because they directly monitor the affected posterior myocardium. The standard chest leads (V1–V3) often show reciprocal ST depressions in posterior MI, and inferior leads (II, III, aVF) reflect a different wall, so they don’t reliably demonstrate posterior wall injury. Anterior leads (V3–V5) aren’t the best view of the posterior wall and may show non-specific or reciprocal changes rather than true ST elevations. Thus, ST elevations in the posterior leads V7–V9 best identify posterior MI.

Posterior MI involves the back wall of the left ventricle, and the electrical changes are best seen on leads that view the posterior surface. To detect this, we place posterior leads on the back that correspond to the same horizontal positions as the chest leads: V7, V8, and V9. In a posterior infarction, these leads show ST elevations because they directly monitor the affected posterior myocardium. The standard chest leads (V1–V3) often show reciprocal ST depressions in posterior MI, and inferior leads (II, III, aVF) reflect a different wall, so they don’t reliably demonstrate posterior wall injury. Anterior leads (V3–V5) aren’t the best view of the posterior wall and may show non-specific or reciprocal changes rather than true ST elevations. Thus, ST elevations in the posterior leads V7–V9 best identify posterior MI.

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