Value of QT dispersion in the interpretation of exercise stress test in women

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