title: Clinical implication of T-wave morphology analysis as a new repolarization descriptor.
abstract: BACKGROUND
  T-wave morphology analysis (TMA) quantifies irregularities of ventricular repolarization based on singular value decomposition of the 12-lead electrocardiogram (ECG). Furthermore, TMA is useful for risk stratification of patients with myocardial infarction (MI), although gender differences in TMA and the relationship between TMA and heart diseases are unknown. The aim of this study was to evaluate the significance of TMA in healthy individuals and patients with heart diseases.
  
  
  RESULTS
  Patients with heart disease and either with or without an implanted cardioverter defibrillator (ICD, n = 33, 57+/-16 years; non-ICD, n = 50, 67+/-10 years) were studied. Normal control ECGs (n = 114) were selected from Marquette's database (NC, 33+/-13 years) and the TMA descriptors, including T-wave morphology dispersion (TMD) and percentage of the loop area (PL), were calculated. TMD was significantly lower in group NC males than in the group NC females (11+/-5.9 vs 22+/-16, p < 0.0001). PL was significantly higher in group NC than in the ICD and non-ICD groups (0.63+/-0.12 vs 0.53+/-0.15, p < 0.0001). TMD of group NC was significantly lower than that of the ICD and non-ICD groups (14+/-11 vs 47+/-27, p < 0.0001).
  
  
  CONCLUSIONS
  There are gender differences in TMD. Abnormal values for TMA could reflect abnormalities of ventricular repolarization.
authors.affiliation: Nippon Medical School, The First Department of Internal Medicine, Tokyo, Japan. takuyawo@nms.ac.jp
authors.forename: Takuya
authors.initials: T
authors.lastname: Ono
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Saitoh
authors.forename: Gang
authors.initials: G
authors.lastname: Yi
authors.forename: Katerina
authors.initials: K
authors.lastname: Hnatkova
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Atarashi
authors.forename: Takao
authors.initials: T
authors.lastname: Katoh
authors.forename: Teruo
authors.initials: T
authors.lastname: Takano
authors.forename: Marek
authors.initials: M
authors.lastname: Malik
mesh_terms: D000368:Aged; D017147:Defibrillators, Implantable; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006329:Heart Conduction System; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000628:therapy; D012307:Risk Factors; D012737:Sex Factors