The U wave explained as an intrinsic part of repolarization

In the ECG the U wave follows the T, which is considered to reflect ventricular repolarization. Several hypotheses about the genesis of the U wave have been put forward, but a satisfactory explanation is still outstanding. We present a simple digital model of the left ventricle that simulates the formation of the U wave on the basis of known electrophysiological processes responsible for the electrical sources in the myocardium, and of the physical laws, embodied in the lead vector concept, which link the potentials in or on the body to these sources. The repolarization waves constructed by the model reproduce the natural aspects of a T wave followed by a U wave. The creation of a U wave appears to be conditional on small voltage differences between the tail ends of the action potentials assigned to the myocardial cells. No fundamental demarcation exists between U wave and preceding T wave.

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