Which leads are best for assessing the left lateral wall of the heart?

Which leads are best for assessing the left lateral wall of the heart?

• A. I and aVL
• B. II and III
• C. aVR and aVF
• D. V1 and V2

Answer: (A)

The left lateral wall of the heart is primarily supplied by the left circumflex artery, and it is best assessed through leads that observe the left precordial and lateral surface of the heart. Leads I and aVL specifically view the left lateral wall, as they are positioned to capture electrical activity occurring in that region.

Lead I looks at the heart from a left-sided perspective, while lead aVL, which is an augmented lead, provides additional emphasis on the upper left side of the heart. Together, these leads form a strong axis to evaluate changes in the left lateral wall, such as ischemia or infarction.

In contrast, leads such as II and III assess the inferior wall of the heart, which does not provide the information relevant to the left lateral wall's condition. Similarly, aVR and aVF focus on different orientations that step away from the left lateral view, with aVR looking more at the right side and aVF capturing the inferior aspect, which again is not useful for assessing the left lateral wall. Lastly, V1 and V2 are positioned more anteriorly and generally reflect the septal area and the anterior wall rather than the lateral aspect of the heart. Therefore, the combination of leads I and aVL is the best