Electrocardiographic measures of repolarization dispersion and their relationships with echocardiographic indices of ventricular remodeling and premature ventricular beats in hypertension.

OBJECTIVE

To examine the relationship between T- T interval (Tpe) and Tpe/QT ratio with occurrence of ventricular premature beats (VPBs) and left ventricular remodeling in hypertension.

METHODS

A total of 52 patients with mild to moderate essential hypertension were included, undergoing echocardiography and 24-hours Holter monitoring. Ventricular remodeling was assessed by left ventricular mass index (LVMI) using the Devereux formula and diastolic function by transmitral E and A wave velocities and E/A ratio. Tpe was measured in the precordial leads. The end of the T wave was set by the method of the tangent to the steepest descending slope of the T wave.

RESULTS

Tpe and Tpe/QT in leads V (r = 0.33, = 0.01; r = 0.27, = 0.04 respectively) and V (r = 0.40, = 0.002; r = 0.40, = 0.003, respectively) correlated significantly with LVMI. A significant inverse relationship was observed between E/A ratio and QT (r = -0.33, = 0.01), Tpe in V (r = -0.39, = 0.003) and Tpe/QT in V (r = -0.31, = 0.02). Tpe in V, V, mean Tpe and maximum Tpe with cut-off values of 60 ms, 59 ms, 62 ms and 71 ms, respectively, associated with the occurrence of ventricular premature beats.

CONCLUSIONS

The repolarization parameters Tpe interval and Tpe/QT ratio correlate with LVMI and indices of left ventricular diastolic function and show better predictive values than traditional parameters such as QT interval and QT dispersion. Lead V is the best lead for measuring Tpe and Tpe/QT. These ECG indices can therefore be used in clinical practice to monitor LV remodeling and predict occurrence of VPBs.