Enhanced Detection of Ischemic but Viable Myocardium by QT Interval Dispersion on Treadmill Exercise Electrocardiograms of Patients with Healed Anterior Wall Myocardial Infarcts

Overview

Journal Clin Cardiol

Specialty Cardiology & Vascular Diseases

Date 2000 Apr 14

PMID 10763076

Citations 1

Authors

Y Koide

M Yotsukura

K Tajino

H Yoshino

K Ishikawa

Affiliations

Soon will be listed here.

Abstract

Background: The presence of ischemic but viable myocardium in infarcted areas is an important indication for coronary revascularization, but is often difficult to detect with the use of treadmill exercise electrocardiography (ECG).

Hypothesis: QT interval dispersion (QTd) is a sensitive method for detecting myocardial ischemia and may improve the accuracy of treadmill exercise ECG testing for detecting ischemic but viable myocardium in infarcted areas.

Methods: Forty-five patients with Q-wave anterior wall myocardial infarctions who underwent treadmill exercise ECG, exercise reinjection thallium-201 (201Tl) scintigraphy, radionuclide angiocardiography, and coronary angiography 1 month after infarction were enrolled in this study. The presence of viable myocardium in the infarct area was determined by exercise reinjection 201Tl scintigraphy. Patients who had no redistribution in the infarct area after reinjection were included in Group 1, and those with redistribution were included in Group 2.

Results: QTd immediately after exercise, and the difference between QTd before and immediately after exercise, were significantly greater in Group 2 than in Group 1. The sensitivity, specificity, and accuracy of conventional ST-segment depression criteria for detecting viable myocardium in the infarct area were 48, 64, and 56%, respectively. The measurement of QTd immediately after exercise (abnormal: > or = 70 ms; normal: < 70 ms) improved the sensitivity, specificity, and accuracy to 78, 82, and 80%, respectively.

Conclusions: This novel diagnostic method using QTd-based criteria significantly improves the clinical usefulness of treadmill exercise ECG testing for detecting ischemic but viable myocardium in infarct areas in patients with healed Q-wave anterior wall myocardial infarctions.

Citing Articles

Value of the corrected QT interval dispersion obtained exercise electrocardiography in determining remote vessel disease in patients with healed Q-wave myocardial infarction.

Altunkeser B, Ozdemir K, Ozdil H, Gok H, Aydin M Ann Noninvasive Electrocardiol. 2002; 7(3):228-33.

PMID: 12167184 PMC: 7027612. DOI: 10.1111/j.1542-474x.2002.tb00168.x.

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