Last update:
15-Nov-2005

Cardiac troponins are proteins of the thin actin filaments of the cardiac muscles. They constitute very sensitive and specific markers for the detection of myocardial damage. The ability to assay their serum levels accurately and quickly has revolutionized the concepts of minor myocardial injury and infarction and serial measurement of troponin I or troponin T has become an important tool for risk stratification of patients presenting with acute coronary syndromes. Unfortunately in spite of the initial enthusiasm for troponin measurements in acute coronary syndromes (ACS), there have been several reports demonstrating a high incidence of elevated troponin levels in a variety of conditions other than acute myocardial necrosis. In contrast to the extensive literature on troponins in ACS, which suggests that abnormal concentrations of cardiac troponins always represent irreversible myocardial damage, there is evidence that these proteins might be released by other mechanisms, such as reversible myocardial ischemia. Consequently, the most important question is not whether or not some other diseases mimic myocardial damage, but rather whether raised troponins reflect reversible or irreversible myocardial injury and how necrosis can be distinguished from reversible myocardial damage. It is therefore of great importance to understand the underlying mechanisms leading to elevated cardiac troponins, besides those of ACS. Further experimental studies are required to clarify this issue. In recent years, numerous clinical studies have showed that raised troponins are predictors for mortality or poor clinical outcome independent of ACS and myocardial infarction.

Key words: Acute coronary syndromes, Cardiac troponins, Myocardial ischemia, Myocardial necrosis.