CVS Practice Test 2026 - Free CVS Practice Questions and Study Guide

The correct choice regarding ST segment elevation in specific leads relates to the blockage of the left circumflex artery (LCX). This phenomenon can be understood within the context of how myocardial infarctions manifest on an electrocardiogram (ECG).

ST segment elevation occurs when there is acute injury to the heart muscle, indicating that the area of the heart supplied by that artery is experiencing ischemia due to insufficient blood flow. Specific leads on the ECG correspond to certain regions of the heart, and the elevation in those leads helps to identify which artery is affected.

In the case of the left circumflex artery, elevation in leads such as V5, V6, and sometimes I and aVL indicates a blockage in the LCX. The distribution of blood flow from the LCX primarily supplies the lateral wall of the left ventricle. Therefore, when there is significant blockage in the LCX, it impacts the electrical activity in these specific leads, resulting in ST segment elevation.

Recognizing these patterns on an ECG is crucial for timely diagnosis and treatment of myocardial infarction, allowing healthcare professionals to target the appropriate artery and intervene effectively.