Correlation of radionuclide estimates of myocardial infarction size and release of creatine kinase-MB in man

Creatine kinase-MB isoenzyme release (CK-MB-g-Eq) was correlated with left ventricular (LV) radionuclide gated blood pool wall motion estimates of percent abnormally contracting regions (%ACR), ejection fraction (EF) and quantitative thallium-201 (Tl-201) LV perfusion scintigraphy (TI-201 perfusion index) during evolving myocardial infarction (MI). Of the 35 patients, 14 had no evidence of either prior MI or right ventricular (RV) MI, and the CK-MB-g-EQ showed reasonable correlation with %ACR (r=0.72; SEE=18.28), with EF (r = -0.78; SEE=0.07) and with the Tl-201 perfusion index (r=0.65; SEE=7.93). In the six patients with prior MI there was no significant correlation between CK-MB-g-Eq and %ACR, EF or Tl-201 perfusion index. Eight other patients had a RVEF that was less than one-half of the LVEF, as well as regional RV wall motion abnormalities, suggesting a combination of LV and RV necrosis. In these patients, there was no significant correlation between CK-MB-g-Eq and %ACR, LVEF or Tl-201 perfusion index. In seven patients with two peaks to their CK-MB release curve, before CK-MB returned to baseline, CK-MB-g-Eq was associated with early %ACR (r=0.71; SEE=21.06), EF (r=-0.81; SEE=0.14) and with the early Tl-201 perfusion index (r=0.78; SEE=6.46), suggesting either that small extensions are beyond the resolution of the radionuclide assessment techniques used in this study or that these patients represent a variant CK-MB release pattern unassociated with extension. These independent radionuclide and enzymatic data suggest that radionuclide techniques may be a reliable clinical method for assessing the extent of LV necrosis during MI. However, limitations may exist in certain cases when either concurrent RV necrosis or prior MI are present.