Masaki Nobuyuki, Takase Bonpei, Matsui Takemi, Kosuda Shigeru, Ohsuzu Fumitaka, Ishihara Masayuki
National Defense Medical College Research Institute, Division of Biomedical Engineering, Tokorozawa Japan.
Heart Rhythm. 2006 Apr;3(4):424-32. doi: 10.1016/j.hrthm.2005.11.030.
The electrocardiographic indices of QT dispersion (QTd), QT peak dispersion (QTpd), and the principal component analysis ratio (PCAr) are related to the occurrence of fatal arrhythmia and are influenced by physical exercise.
The purpose of this study was to investigate whether or not the QT parameters can be used as markers for exercise-induced myocardial ischemia.
We measured these QT parameters at rest and at 3 minutes after exercise using exercise-stress thallium-201 scintigraphy (SPECT), compared with conventional ST segment changes in 161 patients with suspected or known coronary artery disease. The patients were classified into four groups (normal, redistribution, fixed defect, and redistribution with fixed defect) according to SPECT.
At rest, QTd and PCAr were greater in the fixed defect and redistribution with fixed defect groups. PCAr, however, increased after exercise in the redistribution and redistribution with fixed defect groups. Although QTpd at rest was not significantly different among the four groups, it increased in the redistribution and redistribution with fixed defect groups after exercise (QTpd after exercise: normal, 36 +/- 16 ms vs. redistribution, 51 +/- 23 ms, redistribution with fixed defect, 53 +/- 19 ms; P<.05). For myocardial infarction reflected by fixed defect, QTd at rest was the most useful indicator, while QTpd after exercise was the most useful indicator for exercise-induced myocardial ischemia according to multiple logistic regression analysis with receiver operating characteristic curves. In addition, the change in PCAr by exercise was an independent predictor for exercise-induced ischemia.
QTpd and PCAr could be useful indices for exercise-induced myocardial ischemia. Determining the QTpd of a patient after exercising can improve the diagnostic accuracy of ischemia in a routine clinical setting.
QT离散度（QTd）、QT峰离散度（QTpd）和主成分分析比值（PCAr）等心电图指标与致命性心律失常的发生有关，且受体育锻炼影响。
本研究旨在探讨QT参数是否可作为运动诱发心肌缺血的标志物。
我们使用运动负荷铊-201心肌灌注显像（SPECT）在静息状态和运动后3分钟测量这些QT参数，并与161例疑似或已知冠心病患者的传统ST段改变进行比较。根据SPECT将患者分为四组（正常、再分布、固定缺损和再分布合并固定缺损）。
静息时，固定缺损组和再分布合并固定缺损组的QTd和PCAr较大。然而，再分布组和再分布合并固定缺损组运动后PCAr升高。虽然静息时QTpd在四组之间无显著差异，但运动后再分布组和再分布合并固定缺损组的QTpd增加（运动后QTpd：正常组，36±16毫秒；再分布组，51±23毫秒；再分布合并固定缺损组，53±19毫秒；P<0.05）。对于由固定缺损反映的心肌梗死，静息时QTd是最有用的指标，而根据受试者工作特征曲线的多因素逻辑回归分析，运动后QTpd是运动诱发心肌缺血最有用的指标。此外，运动引起的PCAr变化是运动诱发缺血的独立预测因子。
QTpd和PCAr可能是运动诱发心肌缺血的有用指标。在常规临床环境中，测定患者运动后的QTpd可提高缺血诊断的准确性。
