Diagnostic performance of myocardial contrast echocardiography for detection of stunned myocardium

Abstract

Improvement in regional wall motion after acute myocardial infarction has been described up to 2 to 3 weeks after the acute event despite restoration of blood flow by early successful reperfusion therapy. The prospective identification of potentially reversible ventricular dysfunction caused by stunned myocardium has significant clinical implications. Twenty-seven patients with acute myocardial infarction underwent myocardial contrast echocardiography (MCE) before, immediately after, and 4 weeks after successful reperfusion therapy. MCE was performed by imaging a parasternal short-axis view during intracoronary arterial injection of 2 ml sonicated ioxaglate (Hexabrix-320). The contrast defect area and contrast-filled area before reperfusion were defined as the risk area and noninfarct area, respectively. The normalized gray level was defined as the ratio of the gray level in the risk area/gray level in the noninfarct area. In 21 patients, wall motion was akinectic or dyskinetic immediately after reperfusion, and 10 of 21 patients in whom wall motion recovered during the chronic stage were defined as patients with stunned myocardium. In patients who showed asynergic wall motion immediately after reperfusion, MCE predicted the recovery of left ventricular wall motion (stunned myocardium) during the chronic stage with a sensitivity of 77%, specificity of 100%, and predictive accuracy of 86%, when a normalized gray level of more than 0.4 was presumed to predict stunned myocardium. We conclude that MCE provided the prospective identification of potentially reversible ventricular dysfunction caused by stunned myocardium, and wall motion in the area of nonenhanced myocardium on MCE immediately after reperfusion is not expected to show reversible dysfunction.