What EKG finding indicates atrial enlargement?

The presence of notched P waves is indicative of atrial enlargement, particularly left atrial enlargement. This occurs because the increased volume of the atrium leads to a delay in conduction within the atria, which can manifest on the EKG as P waves that are wider and exhibit a distinct notch. The notching represents the prolonged and altered electrical activity that results from the enlarged atrial tissue.

Other EKG findings such as regular P wave morphology typically suggest normal atrial size and function. Inverted P waves often signify a different condition, such as atrial ectopic beats or junctional rhythms, rather than atrial enlargement. Isolated V1 changes are more associated with ventricular abnormalities rather than providing information about atrial size.

Thus, notched P waves are a clear sign of atrial enlargement, aligning with the physiological changes that occur within the atria due to increased workload or volume overload conditions.