The spatial QRS-T angle as a marker of ventricular repolarisation in hypertension

Ventricular repolarisation abnormalities are important in arrhythmia provoc ation. The dispersion of repolarisation duration is not the only aspect of repolarisation heterogeneity. Spatial vectorcardiographic descriptors const itute a novel approach to quantify ventricular repolarisation. To test the ability of vectorcardiographic descriptors to discriminate between hyperten sives with high or low blood pressure (BP), 110 treated hypertensives (mean age 63.6 +/- 12.1 years) were classified in the high (systolic BP greater than or equal to 160 mm Hg or diastolic BP greater than or equal to 95 mm H g) (n = 67), or the low (systolic BP < 160 mm Hg and diastolic BP < 95 mm H g) (n = 43) BP group. The maximum QT, JT, and T peak-T end intervals and th e QT, JT, and T peak-T end dispersion were calculated from a digitally reco rded 12-lead electrocardiogram (ECG), X, Y, and Z leads were reconstructed from the 12-lead EGG. The amplitude of the maximum spatial T vector (spatia l T amplitude), the angle between the maximum spatial QRS and T vectors (sp atial QRS-T angle) and the frontal plane QRS-T angle were calculated. The s patial QRS-T angle was higher in patients with high compared to those with low BP (P = 0.025). All conventional ECG markers of the dispersion of ventr icular repolarisation duration failed to demonstrate significant difference s between hypertensives with high or low BP. In conclusion, the spatial QRS -T angle was significantly increased in those treated hypertensive patients who showed repeatedly high BP values. Hence, we may suggest that the angle between the directions of ventricular depolarisation and repolarisation is a sensitive marker of the repolarisation alterations in systemic hypertens ion.