Exercise-induced post-ischemic left ventricular delayed relaxation or diastolic stunning: is it a reliable marker in
Katsuhisa Ishii1, Makoto Imai, Tamaki Suyama
1Department of Cardiology, Kansai Electric Power Hospital, 2-1-7 Fukushima, Fukushima-ku, Osaka, Japan. ishii.katsuhisa@b2.kepco.co.jp
Objectives:
The aim of this study was to determine whether post-ischemic left ventricular (LV) delayed relaxation could be detected by using strain imaging (SI) derived from 2-dimensional speckle-tracking echocardiography in patients with stable effort angina.
Background:
Regional LV delayed relaxation during early diastole is a sensitive sign of acute myocardial ischemia and may persist beyond recovery of exercise-induced ischemia.
Methods:
Regional LV transverse strain changes during the first one-third of diastole duration (strain imaging diastolic index [SI-DI]) were determined at baseline and 5 and 10 min after the exercise test in 162 patients with stable effort angina. The ratio of SI-DI before and after exercise (SI-DI ratio) was used to identify regional LV delayed relaxation.
Results:
A total of 117 patients had significant (> or =50% of luminal diameter) coronary stenoses. The mean SI-DI decreased from 78.0 +/- 9.7% to 27.6 +/- 16.0% (p < 0.0001) in 191 territories perfused by coronary arteries with significant stenoses 5 min after the treadmill exercise, whereas it remained unchanged in 280 territories perfused by arteries with nonsignificant stenoses. Ten minutes after exercise, regional delayed relaxation was still observed in 85% of territories perfused by stenotic coronary arteries. An SI-DI ratio with a cutoff value of 0.74 had a sensitivity of 97% and a specificity of 93% to detect significant coronary stenosis in the receiver-operator characteristic curve.
Conclusions:
Detection of post-ischemic regional LV delayed relaxation or diastolic stunning after treadmill exercise using SI is a sensitive and reliable method for the detection of coronary artery disease.
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