Chauhan V S, Tang A S
Department of Medicine, University of Ottawa Heart Institute, Ottawa, Ontario, Canada.
J Electrocardiol. 2001 Apr;34(2):109-17. doi: 10.1054/jelc.2001.23116.
QT interval and QT dispersion both prolong early postinfarction. Non-Q wave (NQMI) and Q-wave myocardial infarction (QMI) differ in the extent of transmural necrosis, which may influence these measures of myocardial repolarization. This study compared dynamic changes in QT interval and QT dispersion early postinfarction between NQMI and QMI. In 40 patients with NQMI and 69 patients with QMI, maximum QTc (QTc(max)) and QT dispersion (QTD) were measured during the first 4 days postinfarction. Infarct size was assessed daily by using the Selvester QRS score. In both infarct types, QTc(max) and QTD were prolonged on day 1 of infarction, peaking over the next 2 days before returning toward baseline by day 4. NQMI patients had significantly longer QTc(max) and QTD by days 2 to 3 when compared with QMI patients. Multivariable linear regression identified "infarct type x QRS score" as the only independent predictor of QTc(max) (R(2) =.32, P <.0001) and QTD (R(2) =.19, P <.0001) on day 2. In conclusion, dynamic changes of QTc(max) and QTD occur in both infarct types. Large NQMI is associated with greater prolongation of QTc(max) and QTD, which may be due to greater M cell uncoupling and exposure when compared with QMI.
QT间期和QT离散度在心肌梗死后早期均会延长。非Q波心肌梗死（NQMI）和Q波心肌梗死（QMI）在透壁性坏死程度上有所不同，这可能会影响这些心肌复极指标。本研究比较了NQMI和QMI患者心肌梗死后早期QT间期和QT离散度的动态变化。对40例NQMI患者和69例QMI患者在心肌梗死后的头4天内测量最大QTc（QTc(max)）和QT离散度（QTD）。每天使用塞尔维斯特QRS评分评估梗死面积。在两种梗死类型中，QTc(max)和QTD在梗死第1天延长，在接下来的2天达到峰值，然后在第4天恢复至基线水平。与QMI患者相比，NQMI患者在第2至3天的QTc(max)和QTD明显更长。多变量线性回归分析确定“梗死类型x QRS评分”是第2天QTc(max)（R(2)=.32，P<.0001）和QTD（R(2)=.19，P<.0001）的唯一独立预测因素。总之，两种梗死类型均出现QTc(max)和QTD的动态变化。大面积NQMI与QTc(max)和QTD的更大延长有关，这可能是由于与QMI相比，M细胞解偶联和暴露程度更高所致。
