The U wave has in the past received but little attention in clinical electrocardiography, as its significance was not clear. However, during the last few years methods have been developed which allow electrocardiographic leads to be taken directly from the inside of the heart muscle cell and thus make it possible to obtain new information concerning the significance of the U wave and the electrochemical processes responsible for it. On the other hand, an increasing number of reports is appearing in which changes of the U wave are found to be the chief clue leading toward the correct clinical diagnosis. Furthermore, the study of the U waves may furnish important information concerning the genesis of ventricular arrhythmias.
I first became interested in the U wave and the after-potentials responsible for it almost exactly 20 years ago, when, as a student, I watched the experiments of Drs. C. J. Rothberger and
LEPESCHKIN E. The U Wave of the Electrocardiogram. AMA Arch Intern Med. 1955;96(5):600-617. doi:10.1001/archinte.1955.00250160042004