ECG of a patient had ST segment elevation in VI-V6, lead I and aVL. Which of the following branches is involved?
**Core Concept**
The question is testing the understanding of **coronary artery anatomy** and its relation to **myocardial infarction** patterns on an electrocardiogram (ECG). The ST segment elevation in leads V1-V6, I, and aVL indicates an **acute myocardial infarction** involving the lateral and anterior walls of the heart.
**Why the Correct Answer is Right**
Given the leads involved, the **left anterior descending (LAD) artery** or the **left circumflex artery (LCx)** could be implicated. However, the involvement of leads I and aVL, which look at the lateral wall, along with the anterior leads (V1-V6), suggests a lesion in the **left circumflex artery (LCx)** is less likely for this specific pattern, as LCx typically supplies the lateral and posterior aspects of the heart. The LAD artery supplies the anterior wall and often the lateral wall as well, especially if it wraps around the apex.
**Why Each Wrong Option is Incorrect**
**Option A:** This option might suggest an incorrect artery based on the leads provided.
**Option B:** Similarly, this could be an incorrect assignment based on typical coronary anatomy and the leads affected.
**Option D:** This would be incorrect as it does not align with the coronary anatomy responsible for the ECG changes described.
**Clinical Pearl / High-Yield Fact**
Remember, the **LAD artery** is often referred to as the "widowmaker" because occlusions in this artery can lead to significant anterior wall myocardial infarctions with high mortality if not promptly treated. The distribution of ST elevation can help localize the infarct and suggest which coronary artery is involved.
**Correct Answer:** Correct Answer: C. Left Anterior Descending (LAD) artery