title: Transmural and apicobasal gradients in repolarization contribute to T-wave genesis in human surface ECG.
abstract: The cellular basis of the T-wave morphology of surface ECG remains controversial in clinical cardiology. We examined the effect of action potential duration (APD) distribution on T-wave morphology using a realistic model of the human ventricle and torso. We developed a finite-element model of the ventricle consisting of ∼26 million elements, including the conduction system, each implemented with the ion current model of cardiomyocytes. This model was embedded in a torso model with distinct organ structures to obtain the standard ECG leads. The APD distribution was changed in the transmural direction by locating the M cells in either the endocardial or epicardial region. We also introduced apicobasal gradients by modifying the ion channel parameters. Both the transmural gradient (with M cells on the endocardial side) and the apicobasal gradient produced positive T waves, although a very large gradient was required for the apicobasal gradient. By contrast, T waves obtained with the transmural gradient were highly symmetric and, therefore, did not represent the true physiological state. Only combination of the transmural and the moderate apicobasal gradients produced physiological T waves in surface ECG. Positive T waves in surface ECG mainly originated from the transmural distribution of APD with M cells on the endocardial side, although the apicobasal gradient was also required to attain the physiological waveform.
authors: #381 Environmental Bldg., Kashiwa Campus, The Univ. of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8563, Japan. okada@sml.k.u-tokyo.ac.jp
authors: Jun-Ichi
authors: J
authors: Okada
authors: Takumi
authors: T
authors: Washio
authors: Akiko
authors: A
authors: Maehara
authors: Shin-Ichi
authors: S
authors: Momomura
authors: Seiryo
authors: S
authors: Sugiura
authors: Toshiaki
authors: T
authors: Hisada
mesh_terms: D000200:Action Potentials / Q000502:physiology; D018780:Body Surface Potential Mapping; D003198:Computer Simulation; D004562:Electrocardiography / Q000706:statistics & numerical data*; D055724:Electrophysiological Phenomena / Q000502:physiology; D004699:Endocardium / Q000502:physiology; D020342:Finite Element Analysis; D006321:Heart / Q000502:physiology*; D006329:Heart Conduction System / Q000502:physiology*; D006352:Heart Ventricles; D006801:Humans; D008953:Models, Anatomic; D015233:Models, Statistical; D032383:Myocytes, Cardiac / Q000502:physiology; D010496:Pericardium / Q000502:physiology