Evaluation of cardiac performance and infarct size in acute myocardial infarction

This study was done to evaluate infarct size and ventricular function, simultaneously, in acute myocardial infarction by sup(99m)Tc-pyrophosphate scintigraphy (PYP scan) combined first pass method. Of 36 patients suspected of acute myocardial infarction, 29 patients showed positive uptake of sup(99m)Tc pyrophosphate, the sensitivity and specificity were 90.6 and 100%, respectively. Of positive 29 cases in acute myocardial infarction (AMI), initial and recurrent AMI was 18 and 11 cases, respectively. Correlation between infarct size by PYP scan and left ventricular ejection fraction (LVEF) was R=-0.522 in initial AMI and R=-0.152 in recurrent AMI, respectively. There was significant difference between LVEF in acute phase and that in chronic phase (p<0.01). Comparing acute phase with chronic phase, right ventricular ejection fraction (RVEF) and (LVEF) were improved in 6 of 11 cases and in 9 of 11 cases of intial AMI, respectively; those were improved in 3 of 6 cases and in 5 of 6 cases of recurrent AMI, respectively. sup(99m)Tc-pyrophosphate scintigraphy combined by first pass method could evaluate not only infarct size but also biventricular function of AMI. The assessment of severity of AMI by this combined method will tell prognosis of AMI. (author)