With publication of the studies by Khaw et al. and Beanlands et al. in this issue of the Journal, there is mounting evidence that 99mTc glucarate is taken up by infarcted but not by ischemic myocardium. The early myocardial distribution and rapid blood-pool clearance of 99mTc glucarate suggest important diagnostic potential in the very early detection of acute myocardial infarction and for the identification of successful acute revascularization therapy. To understand the full diagnostic implications of 99mTc glucarate accumulation in the myocardium, larger human trials are now needed. It will be critically important to document the capabilities of 99mTc glucarate to identify, early on, acute myocardial infarction in the presence of a persistently occluded infarct-related coronary artery in human beings.