by Gail Belsky. The term sleep disorder may suggest someone tossing and turning all night, but lying awake for hours with insomnia is just one example of many conditions that affect how you sleep and function during the day. In fact, you can have a sleep disorder and not even know it. Next: How long to snooze.
A U wave as seen on ECG. An electrocardiogram of an 18-year-old man showing U waves, most evident in lead V3. The U wave is a wave on an electrocardiogram that is not always seen. It is typically small, and, by definition, follows the T wave. U waves are thought to represent repolarization of the papillary muscles or Purkinje fibers.
If a U wave is present on an EKG, the nurse should be alert to the fact that hypokalemia may be present. The U wave is normal in some people, but it can be indicative of an electrolyte disturbance. It is best seen in lead V(INSERT LITTLE 3) and is usually quite distinguishable unless it is hidden on the T wave.