Correlation of acute myocardial infarct scintigraphy with postmortem studies.

Acute myocardial infarct scintigraphy with technetium-99m-pyrophosphate was performed in a patient with an acute massive transmural infarct. The patient died 12 hours later, and postmortem tracer studies demonstrated a tracer concentration ratio of 13:1 between acutely infarcted myocardium and normal myocardium remote from the infarct. The concentration of tracer in tissue bordering on the infarct but without histologic evidence of acute infarction was 1.5 times that in normal tissue remote from the infarct. In vitro scintigraphy of the excised heart revealed a pattern of tracer distribution similar to that of scintiscans obtained before death. The biologic distribution of 99mTc-pyrophosphate, with large tracer concentrations only within the acutely infarcted tissue, suggests that acute myocardial infarct scintigraphy can be used to estimate the extent of an acute myocardial infarct.