Dilaveris P, Gialafos E, Pantazis A, Synetos A, Triposkiadis F, Stamatelopoulos S, Gialafos J
State Department of Cardiology, Hippokration Hospital, Greece.
Pacing Clin Electrophysiol. 2001 Feb;24(2):157-65. doi: 10.1046/j.1460-9592.2001.00157.x.
QT dispersion has been proposed to reflect the heterogeneity of ventricular repolarization, but a poor reproducibility limits its clinical usefulness. Spatial vectorcardiographic descriptors constitute a novel approach to quantify ventricular repolarization. To test the ability of vectorcardiographic descriptors to discriminate among different subsets of postinfarction patients, 50 consecutively recruited patients with acute MI, 50 patients with history of an old (> 6 months) MI, and 50 healthy controls were evaluated. The maximum and minimum QT and JT intervals and QT and JT dispersion were manually measured from a digitally recorded 12-lead ECG. X, Y, and Z leads were reconstructed from the 12-lead ECG. The amplitude of the maximum spatial T vector (spatial T amplitude), the angle between the maximum spatial QRS and T vectors (spatial QRS-T angle), and the frontal plane QRS-T angle were automatically calculated. The spatial T amplitude and the spatial QRS-T angle did not differ between patients with a recent and those with an old MI (P = 1). QT dispersion was significantly lower in patients with an old MI than in patients with a recent one (P = 0.002). The spatial repolarization descriptors showed better short-term reproducibility than the dispersion indices. In conclusion, the spatial T amplitude and the spatial QRS-T angle are accurate measures of ventricular repolarization that do not differ between patients with recent and those with old MI. The different QT dispersion values observed in this study between the two post-MI groups should be considered cautiously because of the low accuracy of the manual measurements.
QT离散度被认为可反映心室复极的异质性，但较差的可重复性限制了其临床应用价值。空间向量心电图描述符构成了一种量化心室复极的新方法。为了测试向量心电图描述符区分心肌梗死后不同患者亚组的能力，对50例连续招募的急性心肌梗死患者、50例有陈旧性（>6个月）心肌梗死病史的患者和50例健康对照者进行了评估。从数字记录的12导联心电图中手动测量最大和最小QT及JT间期以及QT和JT离散度。从12导联心电图重建X、Y和Z导联。自动计算最大空间T向量的振幅（空间T振幅）、最大空间QRS和T向量之间的夹角（空间QRS-T夹角）以及额面QRS-T夹角。近期心肌梗死患者和陈旧性心肌梗死患者之间的空间T振幅和空间QRS-T夹角无差异（P = 1）。陈旧性心肌梗死患者的QT离散度显著低于近期心肌梗死患者（P = 0.002）。空间复极描述符显示出比离散度指标更好的短期可重复性。总之，空间T振幅和空间QRS-T夹角是心室复极的准确测量指标，近期心肌梗死患者和陈旧性心肌梗死患者之间无差异。由于手动测量的准确性较低，本研究中观察到的两个心肌梗死后组之间不同的QT离散度值应谨慎考虑。
