
Changes of the t‐wave amplitude and angle: An early marker of altered ventricular repolarization in hypertension
Author(s) -
Dilaveris Polychronis,
Gialafos Elias,
Poloniecki Jan,
Hnatkova Katerina,
Richter Dimitris,
Andrikopoulos George,
Lazaki Elena,
Gialafos John,
Malik Marek
Publication year - 2000
Publication title -
clinical cardiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.263
H-Index - 72
eISSN - 1932-8737
pISSN - 0160-9289
DOI - 10.1002/clc.4960230811
Subject(s) - medicine , repolarization , cardiology , qt interval , ventricular repolarization , left ventricular hypertrophy , electrocardiography , amplitude , electrophysiology , physics , blood pressure , quantum mechanics
Background : The heterogeneity of ventricular repolarization is an important proarrhythmic factor. QT dispersion has been proposed to reflect the inhomogeneity of ventricular repolarization, but a poor reproducibility limits its clinical applicability. Reliable noninvasive methods to quantify abnormalities in ventricular repolarization are still lacking. The T‐loop morphology analysis is a novel method aimed at quantifying ventricular repolarization. Hypothesis : To test the ability of the T‐loop morphology analysis to discriminate between hypertensive patients and healthy subjects, 105 hypertensive patients (mean age 63.6 ± 12.3 years) and 110 healthy controls (mean age 49.7 ± 14.3 years) were evaluated. Methods : The maximum QT interval (QT maximum), the minimum QT interval (QT minimum), and their difference (QT dispersion) were calculated from a digitally recorded 12‐lead electrocardiogram (ECG) in both study groups. X, Y, and Z leads were reconstructed from the 12‐lead ECG, and the amplitude of the maximum T vector (T amplitude) and the angle between the maximum T vector and X axis (T angle) were calculated from the projection of the T loop in the frontal plane. Results : T amplitude (p < 0.001), T angle (p=0.05), and QT dispersion (p = 0.04) were significandy different between hypertensive patients and controls, while QT maximum (p = 0.14) and QT minimum (p = 0.35) did not differ between the groups. T amplitude was the only marker which differed between hypertensive patients without ECG criteria for left ventricular hypertrophy and controls (p = 0.002). Conclusions : T‐loop features and particularly T amplitude are significantly different between hypertensive patients and healthy controls and may serve as early markers of repolarization abnormalities in a hypertensive population.