Which lead provides the best information about atrial enlargement and associated P wave differences?

Which lead provides the best information about atrial enlargement and associated P wave differences?

• A. Lead I
• B. Lead V5
• C. Lead V3
• D. Lead V1

Answer: (D)

Lead V1 is particularly valuable in assessing atrial enlargement and identifying changes in the P wave morphology. This is because V1 is placed in a position that allows a clearer view of the electrical activity occurring in the atria, as it is close to the right atrium.

When atrial enlargement occurs, the P waves can exhibit specific changes; for instance, in right atrial enlargement, the P wave may become taller (peaked), while in left atrial enlargement, it may be wider and have a bifid (notched) appearance. These features are more easily identifiable in the V1 lead due to its unique positioning.

In contrast, while other leads can provide some information about the heart's electrical activity, they do not focus as closely on the atrial electrical signals as V1 does, thereby making them less effective for this specific assessment.