A reverse flow-metabolism mismatch pattern - A new marker of viable myocardium with greater contractility during dobutamine stress than myocardium with a flow-metabolism mismatch pattern

Few studies have investigated the contractility of myocardium with a revers e flow-metabolism pattern; that is, greater uptake of nitrogen-13-ammonia ( NH3) than fluorine-18-fluorodeoxyglucose (FDG) on positron emission tomogra phy (PET). This study examined the contraction thickening represented by co unt increase in EGG-gated FDG-PET of myocardium with a reverse flow-metabol ism pattern during low-dose dobutamine stress. Fifty four patients with myo cardial infarction were studied. Relative NH3 and FDG uptake (%NH3, %FDG) a nd %count increase were measured in 216 apical and 216 lateral segments on EGG-gated FDG-PET. The %count increase during low-dose dobutamine stress wa s greater in myocardium with a reverse flow-metabolism mismatch pattern tha n in myocardium with a flow-metabolism mismatch pattern (35.9+/-25.7% vs 24 .6+/-15.9%, p=0.0221 in apical segments, and 38.4+/-22.6% vs 27.6+/-18.4%, p=0.0040 in lateral segments) despite smaller %FDG. A reverse flow-metaboli sm mismatch pattern should be noted as a new marker of viable myocardium wi th greater contractility during dobutamine stress than myocardium with a fl ow-metabolism mismatch pattern.