METABOLIC IMAGING BY POSITRON EMISSION TOMOGRAPHY EARLY AFTER MYOCARDIAL-INFARCTION AS A PREDICTOR OF RECOVERY OF MYOCARDIAL-FUNCTION AFTERREPERFUSION

Background. Myocardial ischemia leads to alterations in myocardial sub strate metabolism that have been shown to reflect severity of ischemic injury. The purpose of this study was to correlate oxidative metaboli sm with recovery of contractile function in patients with acute myocar dial infarction. Methods and Results. Regional blood flow and oxidativ e metabolism were assessed by dynamic positron emission tomography ear ly after myocardial infarction treated with thrombolytic therapy in 18 patients. The extent of myocardial perfusion abnormality (carbon 11-l abeled acetate uptake; relative amplitude less than or equal to 50%) w as inversely correlated with the ejection fraction obtained within 8 h ours of the onset of chest pain (r = 0.81; p = 0.01) but not clearly w ith that at follow-up 1 week later (r = 0.64; p = 0.09). Oxidative met abolism (carbon 11-labeled acetate; monoexponential clearance) was hig her in periinfarct territories with early or late recovery of contract ile function than in those without, but there was a large overlap in a bsolute values limiting the predictive power of a single measurement. Relatively preserved oxidative metabolism compared with perfusion in l ow-flow areas was predictive of early (day 1 to 1 week) and delayed (w eek 1 to beyond 1 month) recovery. Normal resting perfusion with regio nally decreased oxidative metabolism predicted early recovery of contr actile function. Conclusion. Thus in patients studied with positron em ission tomography early after myocardial infarction, comparison of reg ional perfusion and oxidative metabolism was more predictive of recove ry in contractile function than was assessment of either one alone.