When does the U wave typically appear in an EKG, if it appears?

The U wave is typically seen after the T wave on an EKG. It represents the repolarization of the Purkinje fibers or the end of the ventricular repolarization process. Its appearance indicates that the heart is completing its recovery phase after the electrical impulse has passed through it—this is important in understanding the cardiac cycle phases and electrical activity.

The U wave is not generally associated with the P wave, which correlates with atrial depolarization, or the QRS complex, which reflects ventricular depolarization. The U wave does not occur during systole, as this phase of the cardiac cycle involves contraction and depolarization, rather than repolarization. Therefore, the correct understanding of the U wave's position within the EKG leads to its placement after the T wave.