title: Detection of U wave activity in healthy volunteers by high-resolution magnetocardiography.
abstract: BACKGROUND
  The purpose of our study was to prove the existence of the U wave using magnetocardiograms (MCGs).
  
  
  METHODS
  The 31-channel MCGs of 25 healthy volunteers were recorded. The onset of the U wave was defined by newly developed spatial correlation analysis; and the end, by different approaches.
  
  
  RESULTS
  A U wave could be proved in all volunteers. In 10 volunteers (heart rate, 57 +/- 19 beats/min) in whom the U wave was found to be separated from the following P wave, the U wave's end could be determined as a threshold value (U wave duration, 310 +/- 24 milliseconds). In 15 volunteers (heart rate, 70 +/- 38 beats/min), the end of the U waves was concealed by a continuous transition of the U waves into the following P waves.
  
  
  CONCLUSIONS
  The U wave seems to be a regular phenomenon and has a distinct spatiotemporal assembly.
authors.affiliation: Clinic of Internal Medicine I, University Hospital of Jena, Jena, Germany. matthias.goernig@med.uni-jena.de
authors.forename: Matthias
authors.initials: M
authors.lastname: Goernig
authors.forename: Jens
authors.initials: J
authors.lastname: Haueisen
authors.forename: Mario
authors.initials: M
authors.lastname: Liehr
authors.forename: Markus
authors.initials: M
authors.lastname: Schlosser
authors.forename: Hans R
authors.initials: HR
authors.lastname: Figulla
authors.forename: Uwe
authors.initials: U
authors.lastname: Leder
mesh_terms: D000328:Adult; D000465:Algorithms; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D005260:Female; D005858:Germany; D006329:Heart Conduction System / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D053798:Magnetocardiography / Q000379:methods* / Q000592:standards; D008297:Male; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity