Two-dimensional echocardiography in experimental coronary stenosis. I. Sensitivity and specificity in detecting transient myocardial dyskinesis: comparison with sonomicrometers.
The purpose of this study was to assess the sensitivity and specificity of two-dimensional echocardiography in detecting ischemia-induced transient myocardial dyskinesis. We prepared an open-chest dog model of severe coronary stenosis (90% reduction of circumflex coronary artery diameter) and induced ischemia by acutely raising myocardial oxygen requirements with i.v. isoproterenol and acute aortic constriction. The changes observed with echocardiography were compared with those obtained by intramyocardial sonomicrometers placed side by side or in an endocardial-epicardial orientation. Ischemia was defined as systolic wall expansion or thinning on sonomicrometers and two-dimensional echocardiography. We found complete agreement between sonomicrometers and two-dimensional echocardiography in all control tracings and after ischemia was induced; whenever dyskinesis occurred it was seen by both techniques. Although there was qualitative agreement between echocardiographic and sonomicrometric techniques, there were quantitative differences in the assessment of wall thickening. Such differences may be related to malalignment of the sonomicrometers, echocardiographic resolution limitations or other technical factors. We conclude that two-dimensional echocardiography is a sensitive and specific technique for detecting transient myocardial ischemia, and therefore should be useful for demonstrating exercise-induced ischemia in patients with coronary artery disease.
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