title: [Informative value of orthogonal electrocardiogram in the diagnosis of the left ventricular hypertrophy].
abstract: OBJECTIVE
  To estimate the informative value of orthogonal ECG parameters for the diagnosis of left ventricular hypertrophy (LVH).
  
  
  METHODS
  The study comprised 142 apparently healthy individuals and 125 patients with arterial hypertension (AH) and LVH (left ventricular mass index more than 125 g/m2 for males and more than 110 g/m2 for females). Characteristic curves (ROC curves) were used to describe and compare the informative value of vectorcardiographic, demapping criteria for L VH with the informavalue of the Sokolov-Lyons criterion, the Cornelian index, and the Cornelian product.
  
  
  RESULTS
  The informative indices of orthogonal ECG were Rx + Sz and IADIM: the area under the ROC curve was 0.89 +/- 0.02 and 0.88 +/- 0.02, respectively, which was significantly higher than with the Sokolov-Lyons criterion (0.64 +/- 0.04; p < 0.05) and similar to the Cornelian product (0.84 +/- 0.03). Of great informative value is the angle phi (area under the ROC curve was 0.88 +/- 0.04) in males and the area of QRS loop in the horizontal plane (area under the ROC curve was 0.89 +/- 0.03) in females. With 96% specificity, the male sensitivity of IADIM was 80%, Rx + Sz--73%, which was significantly higher than that of the Cornelian index (56%; p < 0.05) and the Sokolov-Lyons criterion (27%; p < 0.05). With 96% specificity, the female sensitivity of IADIM was 73%, Rx + Sz--84%, SQRSxz--70%, which was significantly higher than that of the Cornelian index (49%; p < 0.05), the Cornelian product (55%; p < 0.05), and the Sokolov-Lyons criterion (30%; p < 0.05).
  
  
  CONCLUSIONS
  The threshold values of the most informative indices of orthogonal ECG are presented, which could provide the optimum sensitivity-specificity ratios. These values allow cardiac lesions to be detected in hypertensive patients with normal 12-lead ECG.
authors.forename: E V
authors.initials: EV
authors.lastname: Blinova
authors.forename: T A
authors.initials: TA
authors.lastname: Sakhnova
authors.forename: M A
authors.initials: MA
authors.lastname: Saidova
authors.forename: E V
authors.initials: EV
authors.lastname: Oshchepkova
authors.forename: E A I
authors.initials: EA
authors.lastname: Aĭdu
authors.forename: V G
authors.initials: VG
authors.lastname: Trunov
authors.forename: L I
authors.initials: LI
authors.lastname: Titomir
mesh_terms: D000328:Adult; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications*; D017379:Hypertrophy, Left Ventricular / Q000150:complications / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted