Troponin I is a sensitive and specific biochemical marker, as a gold standard, for the diagnosis of myocardial infarction, might replace the classic cardiac enzymes as total CK, CK-MB, AST in this diagnosis. Although being the most heart-specific enzyme, CK-MB concentration only increases lately during a short period of acute myocardial infarction (6). Based on the study of 126 patients suffering from acute myocardial infarction treated at the Viet Tiep Hospital of Hai Phong. The authors observed that: Troponin I is a valuable marker for the early diagnosis of acute myocardial infarction without changes of cardiac enzymes CK total and CK-MB. During the period of increasing of the concentrations of these cardiac enzymes, troponin I level has positive correlation (r = 0:54, p 0.01) with these concentrations. In acute myocardial infarction, both total cholesterolemia and LDL-C increase.