title: The peak-to-end of the T wave in the limb ECG leads reflects total spatial rather than transmural dispersion of ventricular repolarization in an anthopleurin-A model of prolonged QT interval.
abstract: BACKGROUND
  Previous studies have showed that the interval between the peak and the end of the T wave (Tp-e) is a marker of transmural dispersion of ventricular repolarization.
  
  
  OBJECTIVE
  We studied the relationship between (a) the Tp-e on local pseudo transmural electrograms (pseudo transmural Tp-e) or limb leads of body surface electrocardiogram (surface Tp-e) and (b) the intracardiac left ventricular (LV) repolarization during a drug-induced QT-interval prolongation.
  
  
  METHODS
  Using open-chested canine intact hearts treated by anthopleurin-A, transmural LV electrograms were recorded via needle electrodes placed in the basoanterior, midanterior, apicoanterior, basolateral, midlateral, and apicolateral LV wall. Recovery time (RT) was calculated as an index of local repolarization at each transmural unipolar electrode.
  
  
  RESULTS
  This model showed slower heart rate-dependent heterogeneous distribution of ventricular repolarization both along the basal to apical axis and along the transmural axis. RT was longer at the LV apex than at the base and longer in the lateral than in the anterior wall during the slower heart rate. A high correlation was found between surface Tp-e and total LV dispersion. In contrast, pseudo transmural Tp-e correlated with transmural RT dispersion. The shortest RT in the heart roughly corresponded to the peak, as did the longest RT with the end of the T wave on the surface electrocardiogram.
  
  
  CONCLUSIONS
  During drug-induced QT-interval prolongation with a large apicobasal and anterolateral dispersion of ventricular repolarization, the Tp-e in the limb leads expresses spatial (total) distribution of repolarization in the whole left ventricle.
authors: First Department of Internal Medicine, Niigata University School of Medicine, Niigata, Japan.
authors: Daisuke
authors: D
authors: Izumi
authors: Masaomi
authors: M
authors: Chinushi
authors: Kenichi
authors: K
authors: Iijima
authors: Hiroshi
authors: H
authors: Furushima
authors: Yukio
authors: Y
authors: Hosaka
authors: Kanae
authors: K
authors: Hasegawa
authors: Yoshifusa
authors: Y
authors: Aizawa
mesh_terms: D000818:Animals; D004285:Dogs; D004562:Electrocardiography; D004567:Electrodes, Implanted; D006329:Heart Conduction System / Q000503:physiopathology*; D006352:Heart Ventricles / Q000503:physiopathology*; D036341:Intercellular Signaling Peptides and Proteins; D008133:Long QT Syndrome / Q000139:chemically induced / Q000503:physiopathology*; D010455:Peptides
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; C012746:anthopleurin-A