What does the U wave represent if seen on an EKG?

The U wave on an electrocardiogram (EKG) is considered to represent post-repolarization waves. It typically follows the T wave and can indicate the completion of repolarization of the myocardium (heart muscle). While the exact origin of the U wave is not fully understood, it is thought to be related to the repolarization processes of the ventricles.

U waves can be more prominent in certain conditions such as hypokalemia, which is a low potassium level in the blood, but are normally considered a variant of repolarization waves. Recognizing the U wave and understanding its significance is important for interpreting the overall cardiac electrical activity and for assessing potential underlying conditions that may affect heart health.