title: The T-peak-T-end interval as a marker of repolarization abnormality: a comparison with the QT interval for five different drugs.
abstract: OBJECTIVE
  The T-peak to T-end (TpTe) interval has been suggested as an index of transmural dispersion and as a marker of drug-induced abnormal repolarization. In this study, we investigate the relation between TpTe and the QT interval.
  
  
  METHODS
  Electrocardiograms (ECGs) from five different drugs (sotalol, sertindole, moxifloxacin, nalmefene, and Lu 38-135) and from a placebo group were analyzed. Semi-automatic measurements of T-peak, T-end, and QRS onset were obtained. The TpTe/QT ratio was calculated to investigate the proportional relationship of QT and TpTe.
  
  
  RESULTS
  Although a significant increase of both TpTe and QT from baseline is apparent with QT-prolonging drugs, the TpTe/QT ratio remained the same at baseline and after drug administration, thus indicating that prolongation of TpTe is just a fractional part of total QT prolongation. In the presence of notched or flattened T-waves, the uncertainty associated with measurement of the TpTe interval increases. The errors in TpTe for individual subjects may be substantial, thus complicating the use of TpTe for follow-up of individuals.
  
  
  CONCLUSIONS
  The duration of the QT interval and TpTe are closely related. Drugs appear to prolong the TpTe interval as a predictable fraction of the total QT prolongation.
authors.affiliation: Department of Health Science and Technology, Aalborg University, Frederik Bajers vej-7 C1, 9220, Aalborg, Denmark. tb@hst.aau.dk.
authors.forename: Tanveer A
authors.initials: TA
authors.lastname: Bhuiyan
authors.affiliation: Department of Health Science and Technology, Aalborg University, Frederik Bajers vej-7 C1, 9220, Aalborg, Denmark.
authors.forename: Claus
authors.initials: C
authors.lastname: Graff
authors.affiliation: Laboratory of Experimental Cardiology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.|Department of Cardiology, Herlev and Gentofte University Hospitals, Copenhagen, Denmark.
authors.forename: Jørgen K
authors.initials: JK
authors.lastname: Kanters
authors.affiliation: Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.|Psychiatry, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Jimmi
authors.initials: J
authors.lastname: Nielsen
authors.affiliation: Department of Health Science and Technology, Aalborg University, Frederik Bajers vej-7 C1, 9220, Aalborg, Denmark.
authors.forename: Jacob
authors.initials: J
authors.lastname: Melgaard
authors.affiliation: Global Pharmacovigilance, H. Lundbeck A/S, Copenhagen, Denmark.
authors.forename: Jørgen
authors.initials: J
authors.lastname: Matz
authors.affiliation: Department of Health Science and Technology, Aalborg University, Frederik Bajers vej-7 C1, 9220, Aalborg, Denmark.|College of Medicine, Qatar University, Doha, Qatar.
authors.forename: Egon
authors.initials: E
authors.lastname: Toft
authors.affiliation: Department of Health Science and Technology, Aalborg University, Frederik Bajers vej-7 C1, 9220, Aalborg, Denmark.
authors.forename: Johannes J
authors.initials: JJ
authors.lastname: Struijk
mesh_terms: D000328:Adult; D015415:Biomarkers; D002986:Clinical Trials as Topic; D004095:Dihydropyridines / Q000009:adverse effects*; D004562:Electrocardiography / Q000187:drug effects*; D005260:Female; D024841:Fluoroquinolones / Q000009:adverse effects*; D006801:Humans; D007093:Imidazoles / Q000009:adverse effects*; D007211:Indoles / Q000009:adverse effects*; D008297:Male; D000077266:Moxifloxacin; D009271:Naltrexone / Q000009:adverse effects / Q000031:analogs & derivatives*; D004364:Pharmaceutical Preparations; D013015:Sotalol / Q000009:adverse effects*
chemical_list: C527164:3-(1-(2-(1-acetyl-2,3-dihydro-1H-indol-3-yl)ethyl)-3,6-dihydro-2H-pyridin-4-yl)-6-chloro-1H-indole; D015415:Biomarkers; D004095:Dihydropyridines; D024841:Fluoroquinolones; D007093:Imidazoles; D007211:Indoles; D004364:Pharmaceutical Preparations; D009271:Naltrexone; D013015:Sotalol; C066304:sertindole; C038981:nalmefene; D000077266:Moxifloxacin