Stoletniy L N, Pai R G
Section of Cardiology, Loma Linda University and VA Medical Center, Calif, USA.
Circulation. 1997 Aug 5;96(3):904-10. doi: 10.1161/01.cir.96.3.904.
Exercise testing in women is associated with a high incidence of false-positive ECG changes and should be combined with an imaging study. The QT dispersion (QTD), recorded as the difference between maximum and minimum QT intervals on a 12-lead ECG, is sensitive to myocardial ischemia and may improve the accuracy of exercise testing in women.
Exercise ECGs were analyzed in 64 women who had undergone exercise ECG and coronary angiography for clinical indications: 20 patients with normal exercise stress test and nonsignificant (< or = 50% diameter narrowing of a major epicardial coronary artery) coronary artery disease (CAD) on angiography (true-negative; TN group), 20 patients with positive exercise stress tests (> or = 1 mm ST-segment depression or reversible perfusion defects) and significant CAD (true-positive; TP group), and 24 patients with positive exercise stress tests but no significant CAD (false-positive; FP group). The exercise QTD was 45+/-15 ms in TN, 80+/-23 ms in TP (P<.0001 versus TP), and 41+/-14 ms in FP (P=NS versus TN and <.0001 versus TP) groups. A stress QTD of > 60 ms had a sensitivity of 70% and specificity of 95% for the diagnosis of significant CAD compared with 55% (P<.05) and 63% (P<.01), respectively, for > or = 1 mm ST-segment depression during stress. When QTD of > 60 ms was added to ST-segment depression as a condition for positive test, the specificity increased to 100%.
Exercise QTD is an easily measurable ECG variable that significantly increases the accuracy of exercise testing in women.
女性运动试验与心电图改变假阳性的高发生率相关，应与影像学检查相结合。QT离散度（QTD）记录为12导联心电图上最大和最小QT间期的差值，对心肌缺血敏感，可能提高女性运动试验的准确性。
对64例因临床指征接受运动心电图和冠状动脉造影的女性进行运动心电图分析：20例运动应激试验正常且血管造影显示冠状动脉疾病（CAD）不显著（主要心外膜冠状动脉直径狭窄≤50%）的患者（真阴性；TN组），20例运动应激试验阳性（ST段压低≥1mm或可逆性灌注缺损）且CAD显著的患者（真阳性；TP组），以及24例运动应激试验阳性但CAD不显著的患者（假阳性；FP组）。TN组运动QTD为45±15ms，TP组为80±23ms（与TP组相比，P<0.0001），FP组为41±14ms（与TN组相比，P=无显著性差异；与TP组相比，P<0.0001）。应激QTD>60ms诊断显著CAD的敏感性为70%，特异性为95%，而应激时ST段压低≥1mm的敏感性和特异性分别为55%（P<0.05）和63%（P<0.01）。当将QTD>60ms作为阳性试验条件加入ST段压低时，特异性提高到100%。
运动QTD是一个易于测量的心电图变量，可显著提高女性运动试验的准确性。
