Nakajima T, Fujimoto S, Uemura S, Kawamoto A, Doi N, Hashimoto T, Dohi K
First Department of Internal Medicine, Nara Medical University, Kashihara, Japan.
J Electrocardiol. 1998 Jan;31(1):1-8. doi: 10.1016/s0022-0736(98)90001-2.
QT dispersion has been recognized as an undesirable marker because of its association with arrhythmogenicity in patients with myocardial infarction, but the relation between QT interval dispersion and wall motion abnormalities has not been clarified. After the introduction of reperfusion therapy, it was recognized that T waves were inverted twice in the course of myocardial infarction. An investigation was made of the clinical significance of QT dispersion in relation to the presence of inverted T waves and left ventricular wall motion abnormalities in 34 patients (mean age, 59 years) with acute anterior myocardial infarction who underwent successful reperfusion therapy. The amplitude of the deepest inverted T waves occurring within the first 3 days (T1) and after 3 days (T2) of myocardial infarction were measured in electrocardiographic (ECG) lead V3. On the ECGs on which T1 and T2 were recorded, QT dispersion was calculated (QTd1, QTd2), and T1 and T2 were correlated with QTd1 (r = .65) and QTd2 (r = .47), respectively. The difference between the extent of asynergy in the acute phase and the chronic phase, which was evaluated by the centerline method, was correlated with T1 (r = .63) and QTd1 (r = .67). Patients with a QTd1 of 0.1 second or longer showed a greater change in the extent of asynergy (23.4 +/- 13.1% vs 4.9 +/- 9.8%, P < .01) and less asynergy in the chronic phase (19.9 +/- 15.6% vs 46.5 +/- 14.0%, P < .01) than patients with a QTd1 of less than 0.1 second. Thus, QT dispersion in the acute phase of anterior myocardial infarction indicates recovery of left ventricular wall motion. Prolongation of the local action potential duration of the myocardium that recovers from severe ischemia may be a contributor to the increased QT dispersion that results in inversion of T waves in the acute phase of myocardial infarction.
QT离散度已被公认为是一个不良指标，因为它与心肌梗死患者的心律失常性有关，但QT间期离散度与室壁运动异常之间的关系尚未阐明。在引入再灌注治疗后，人们认识到在心肌梗死过程中T波会出现两次倒置。对34例（平均年龄59岁）接受成功再灌注治疗的急性前壁心肌梗死患者，就QT离散度与T波倒置及左心室壁运动异常的关系进行了临床意义的研究。在心电图（ECG）导联V3中测量心肌梗死第1个3天内（T1）和3天后（T2）出现的最深倒置T波的振幅。在记录有T1和T2的心电图上，计算QT离散度（QTd1、QTd2），且T1和T2分别与QTd1（r = 0.65）和QTd2（r = 0.47）相关。通过中心线法评估的急性期与慢性期协同失调程度的差异与T1（r = 0.63）和QTd1（r = 0.67）相关。QTd1为0.1秒或更长的患者与QTd1小于0.1秒的患者相比，协同失调程度变化更大（23.4±13.1%对4.9±9.8%，P < 0.01），且慢性期协同失调程度更小（19.9±15.6%对46.5±14.0%，P < 0.01）。因此，前壁心肌梗死急性期的QT离散度提示左心室壁运动的恢复。从严重缺血中恢复的心肌局部动作电位时程延长可能是导致心肌梗死急性期QT离散度增加并引起T波倒置的一个因素。
