737–2 Heart Fatty Acid-binding Protein can Provide a Higher Level of Accuracy than Myoglobin for the Early Detection of Acute Myocardial Infarction

Abstract

Heart fatty acid-binding protein (HFABP) is a cytoplasmic low molecular weight protein similar to myoglobin (Mb). The skeletal muscle Mb content is approximately twice that of the heart while the HFABP concentration in striated muscle is only 10–50% of that in cardiac muscle. To evaluate the usefulness of HFABP for the early detection of acute myocardial infarction (AMI), we measured serum HFABP and Mb levels in the initial samples in 114 patients (pts) brought to our coronary care unit within 3 hours following onset of symptoms. AMI was confirmed in 63 pts by history, ECG changes and the pattern of serum CKMB release and was excluded in 51 pts. HFABP was measured by competitive enzyme immunoassay and Mb by latex agglutination turbidimetry. HFABP in the 63 pts with AMl (mean ± SD, 58 ± 50 ng/ml) significantly (p < 0.01) exceeded those in the pts without AMI (8.8 ± 6.2 ng/ml). Figure shows the receiver operating characteristic (ROC) curves for the detection of AMI within 3 hrs of the onset (1.9 ± 0.7 hrs). The upward and leftward shift in the ROC curve was greater for the HFABP than the Mb. The sensitivity and specificity of HFABP > 14 ng/ml (mean + 2SD in 50 healthy volunteers) for the detection of AMI within 3 hours of the onset were 73% and 80%, respectively. Those of Mb > 88 ng/ml(mean + 2SD in 50 healthy volunteers) were 73% and 61%, respectively. HFABP could provide a higher level of accuracy than the Mb for detecting AMI within 3 hours of the onset.