How can you identify atrial enlargement on an EKG?

Identifying atrial enlargement on an EKG involves analyzing the characteristics of the P wave, which represents atrial depolarization. A wide and notched P wave is a classic sign of atrial enlargement, specifically indicating that one or both atria are enlarged. This notable change in the P wave morphology occurs because as the atria grow larger, the depolarization takes longer and spreads out unevenly, resulting in a wider and sometimes notched appearance.

In cases of right atrial enlargement, the P wave might be taller, while left atrial enlargement commonly presents as a notched P wave. The presence of the notch reflects the delayed activation of the enlarged left atrium. Therefore, this specific characteristic directly correlates to the underlying cardiac changes associated with atrial enlargement, making it the correct method for identifying this condition on an EKG.

The other options focus on different aspects of the EKG, such as T wave characteristics and QRS complex width, which do not relate directly to atrial enlargement. Thus, they would not be used to identify this particular issue.