Usefulness of myoglobin radioimmunoassay determintion in CCU.
In 112 patients with an acute coronary event, admitted to the CCU of Assaf-Harofeh Hospital, myoglobin radioimmunoassay was determined at 0 (time of admission), 12 and 24 hours. In 77 patients with acute myocardial infarction (M.I.) (64 patients with acute transmural and 13 with acute subendocardial M.I.), the myoglobin values were significantly increased. Appearing in blood 3-4 hours after the onset of chest pains, myoglobin represents the earliest marker of acute M.I. known until know. In 12 of 23 cases diagnosed at first as acute coronary insufficiency according to clinical, biological and E.C.G. criteria, significantly increased values of myoglobin were found, as an expression of micro-necroses which were not detected by conventional methods (SGOT, CPK, LDH). This finding has important practical, prognostic and therapeutical implications, showing that myoglobin radioimmunoassay may detect myocardial micronecroses which are not discovered by usual methods. Myoglobin radioimmunoassay assessment offers a valuable indication of necrosis extent. Values above 800 ng/ml were accompanied in 65% of our cases with symptoms and signs of left heart failure, the highest values of myoglobin being found in extensive anterior M.I. associated with acute pulmonary edema. In 9 non cardiac patients with repeated intra-muscular injections with antibotics, the myoglobin was at the upper normal limit, demonstrating that intra-muscular injections, at least with antibiotics, have no influence on myoglobin values. From our experience it appears that the myoglobin radioimmunoassay determination is a useful tool for the early establishment of M.I. diagnosis and the assessment of myocardial necrosis extent.