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

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.