Kesek Milos, Englund Anders, Jernberg Tomas, Lagerqvist Bo, Lindahl Bertil
Department of Cardiology, Norrland University Hospital, 90185 Umea, Sweden.
Ann Noninvasive Electrocardiol. 2003 Jan;8(1):22-9. doi: 10.1046/j.1542-474x.2003.08105.x.
QT dispersion (QTd) contains prognostic information in several patient groups. The variable increases in several conditions with ischemia. Originally, it was thought to reflect the local repolarization inhomogeneity. Even though this explanation has been questioned lately, it continues to be put forward. In order to elucidate a possible local mechanism, we investigated the relation between QT dispersion, an ECG parameter reflecting the local dispersion, and angiographical measures in a population with unstable coronary artery disease.
The 276 patients were recruited from the FRISC II trial. As the QTd parameter we used the mean value of automatically measured QTd during 27 hours after admission (QTdMean). As a local repolarization measure we used the maximal difference in QT between two adjacent ECG leads (QTdiffMean). The computations were performed on all available ECG leads and on a restricted set without the V1-V2 combination. Previously published angiographic scoring tools were adapted for rating and localizing the coronary pathology by two approaches and applied on 174 patients undergoing angiography.
QTdMean was significantly higher than that reported in previous material with unselected chest pain patients (55 vs 40 ms). QTdiffMean correlated strongly with QTdMean. No differences in QTdMean were detected between patients with different angiographical scores. No relation could be shown between the region with dominating coronary pathology as expressed by the scoring tools and the localization of QTdiffMean.
QTd in ischemia seems to be increased by a mechanism unrelated to localization and severity of coronary disease.
QT离散度（QTd）在多个患者群体中包含预后信息。在几种伴有缺血的情况下该变量会增加。最初，人们认为它反映局部复极的不均匀性。尽管这种解释最近受到质疑，但仍不断有人提出。为了阐明可能的局部机制，我们在不稳定型冠状动脉疾病患者群体中研究了反映局部离散度的心电图参数QT离散度与血管造影测量结果之间的关系。
276例患者来自FRISC II试验。作为QTd参数，我们使用入院后27小时内自动测量的QTd平均值（QTdMean）。作为局部复极测量指标，我们使用两个相邻心电图导联之间QT的最大差值（QTdiffMean）。计算在所有可用的心电图导联上进行，也在不包括V1 - V2组合的受限导联集上进行。以前发表的血管造影评分工具通过两种方法进行调整以对冠状动脉病变进行评级和定位，并应用于174例接受血管造影的患者。
QTdMean显著高于先前报道的未选择胸痛患者的材料中的值（55对40毫秒）。QTdiffMean与QTdMean密切相关。不同血管造影评分的患者之间未检测到QTdMean的差异。评分工具所表示的主要冠状动脉病变区域与QTdiffMean的定位之间未显示出相关性。
缺血时的QTd似乎是通过一种与冠状动脉疾病的定位和严重程度无关的机制增加的。
