Cardiac Medicine Certification (CMC) Practice Exam

What does the presence of ST depressions in V1-V6 suggest about myocardial infarction location?

1. Anterior wall MI

2. Lateral wall MI

3. Posterior wall MI

4. Inferior wall MI

The correct answer is: Posterior wall MI

The presence of ST depressions in the leads V1-V6 typically suggests myocardial ischemia or infarction, specifically pointing toward a posterior wall myocardial infarction. In the setting of a posterior wall MI, changes in the anterior leads (V1-V2) may manifest as ST depression due to the vector of the ischemic process. In contrast, an anterior wall MI would more commonly present with ST elevations in the anterior leads rather than depressions. Lateral wall MIs, reflected in leads I, aVL, V5, and V6, generally exhibit ST elevations or potentially T-wave inversions rather than ST depressions in V1-V6. Inferior wall MIs would primarily affect leads II, III, and aVF, making them unrelated to the ST depressions in the anterior leads. Therefore, the presence of ST depressions in V1-V6 is indicative of a posterior wall myocardial infarction, as this pattern reflects the underlying ischemia impacting the posterior segments of the heart as observed in the anterior leads.