<P> The' U' wave is a wave on an electrocardiogram (ECG). It is the successor of the' T' wave and may not always be observed as a result of its small size .' U' waves are thought to represent repolarization of the Purkinje fibers . However, the exact source of the U wave remains unclear . The most common theories for the origin are: </P> <Ul> <Li> Delayed repolarization of Purkinje fibers </Li> <Li> Prolonged re-polarisation of mid-myocardial M - cells </Li> <Li> After - potentials resulting from mechanical forces in the ventricular wall </Li> <Li> The repolarization of the papillary muscle . </Li> </Ul>

What is the u wave on an ekg
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