U wave
ECG waveform / From Wikipedia, the free encyclopedia
The U wave is a wave on an electrocardiogram (ECG). It comes after the T wave of ventricular repolarization and may not always be observed as a result of its small size. 'U' waves are thought to represent repolarization of the Purkinje fibers.[1][2] However, the exact source of the U wave remains unclear. The most common theories for the origin are:
- Delayed repolarization of Purkinje fibers
- Prolonged re-polarisation of mid-myocardial M-cells
- After-potentials resulting from mechanical forces in the ventricular wall
- The repolarization of the papillary muscle.[3]