Which lead configuration provides the best view of the heart's lateral wall?

The configuration of Leads I and aVL provides an optimal view of the heart's lateral wall because both of these leads are positioned to capture electrical activity from the left side of the heart. Lead I measures the electrical potential between the right arm and the left arm, providing a view of the lateral aspect of the heart, while aVL, which is an augmented unipolar lead, also focuses on the left side but from a slightly different angle. This combination allows for a comprehensive assessment of the lateral wall, which is primarily supplied by the left circumflex artery.

The other configurations do not offer as effective a view of the lateral wall. Leads V1 and V2 are generally oriented towards the anterior portion of the heart, providing insight into the right ventricle and septal activity. Leads II and III are positioned to capture inferior wall activity, primarily focusing on the lower regions of the heart. Leads V3 and V4, while providing some lateral view, are primarily aimed at the anterior wall and do not focus directly on the lateral wall as effectively as Leads I and aVL. Thus, the choice of Leads I and aVL is well-supported by their anatomical positioning relative to the lateral aspect of the heart.