Dipyridamole Echocardiography in the Detection of Vulnerable Myocardium in the Early Postinfarction Period

To evaluate the effect of dipyridamole on regional wall motion after myocardial infarction two-dimensional echocardiograms were obtained on 21 postinfarction patients immediately before and 7 to 10 minutes after the intravenous infusion of dipyridamole (0.60 mg/kg). All patients underwent coronary angiography, and 20 patients underwent scintigraphy with dipyridamole thallium immediately subsequent to dipyridamole echocardiography. Dipyridamole augmented noninfarct zone regional wall motion in 20 of 31 regions supplied by nonstenotic coronary arteries. In contrast, only one of eight regions of noninfarct zone myocardium supplied by coronary arteries with greater than a 70% luminal diameter narrowing (vulnerable myocardium) was able to augment the regional wall motion subsequent to dipyridamole administration (p = 0.05). Dipyridamole echocardiography appears to be a safe and sensitive technique that may be useful in the detection of vulnerable myocardium in the early postinfarction period.