Quantitative repolarization indices in diagnosis of left ventricular hypertrophy in hypertensive patients

Abstract

Aim. To determine informative value of quantitative parameters of orthogonal ECG repolarization phase in diagnosis of left ventricular hypertrophy (LVH) in hypertensive patients. Material and methods. A total of 210 healthy subjects and 241 hypertensive patients with LVH (LV myocardium mass index > 125 g/m2 in males and > 110 g/m2 in women) comprised two groups - control and test. The study was made of quantitative parameters (components X, Y, Z, modules and angles of azimuth and elevation) of wave T integral vector, wave T maximal vector, ST vector, ventricular gradient; spatial and projection areas of wave T, the angle between integral vectors of spatial waves QRS and T (phi angle). Results. The test group had reduced X, Y components and elevated vectors, their azimuth and phi angle. Most informative for repolarization were components X of T maximal and integral vectors being as informative as Rx+Sz and Cornel product. The method of multiple regression analysis was used to plot discriminant function taking account of most informative indices of depolarization and repolarization - Rx+Sz and X component of T maximal vector. The area under ROC curve for this function was greater than for the variables alone and Cornel product in both groups (0.90 ± 0.02 and 0.86 ± 0.02, p < 0.05 for the control and test group, respectively). Conclusion. Quantitative parameters of repolarization phase can improve LVG diagnosis in hypertensive patients.

Keywords

• left ventricular hypertrophy
• arterial hypertension
• electrocardiography
• orthogonal leads
• repolarization