Metabolism and blood flow as new markers of myocardial viability in the evolution of myocardial infarction

Animal studies have shown that increased regional ¹⁸F-deoxyglucose (FDG) uptake as demonstrated by positron emission tomography (PET) in ischemic and reperfused myocardium reflects reversible tissue injury. Therefore, we studied patients with acute myocardial infarction to define the extent and severity of injury. Left ventricular segments with reduced blood flow and metabolism, as demonstrated by matching defects of flow and FDG uptake, revealed irreversible injury as evidenced by lack of functional recovery. In contrast, segments with reduced flow but maintained FDG uptake showed variable functional outcome with improvement of the average wall motion score. Thus, PET may be useful in identifying myocardium at risk which may benefit from therapeutic interventions.