Pattern and Molecular Mechanisms of Cardiac Troponin Release in Conditions Other than Acute Coronary Syndromes

easurements of cardiac troponin concentrations are at present universally accepted and recommended as the gold standard biochemical methods for diagnosis of acute myocardial infarction (AMI) in patients presenting with chest pain. In addition, levels of cardiac troponin T (cTnT) and troponin I (cTnI) provide useful prognostic information and can help to guide the management of acute coronary syndrome (ACS) patients. Nonetheless, although the currently available troponins have a nearly absolute cardiac specificity, they are not disease specific and cannot be used to distinguish reversible from irreversible myocardial cell injury. According to the new criteria of international cardiology societies, the definitive diagnosis of AMI can be made in the presence of a rise and/or fall of cardiac troponins (or CK-MB mass when the troponins are not available) together with ischemic symptoms, electrocardiographic changes indicative of new ischemia, or imaging evidence of new loss of viable myocardium or new regional wall motion abnormality. Thus, the presence of significant changes in troponin levels is essential for the diagnosis of myocardial cell necrosis. There is, however, thus far no consensus about the extent of these changes should be. Some experts have suggested a troponin change of 20% or more, but as has recently been reported, the intra-individual biological variability of troponin concentrations in healthy persons can be higher than 50% and thus, should be considered in the interpretation of tests results. Another biochemical characteristic of myocardial cell necrosis due to obstructive coronary artery disease is the prolonged elevation of cardiac troponins beyond 1 week. This pattern of cardiac troponin release can be explained by the initial egress of the free (unbound) troponins from the cytosolic pool (3-7% of the total troponin content), Pattern and Molecular Mechanisms of Cardiac Troponin Release in Conditions Other than Acute Coronary Syndromes