The twilight zone of troponins.

Since its introduction into the clinical environment in the early nineties, the cardiac enzyme troponin has significantly changed the way we diagnose and manage acute coronary syndromes. Troponin I is a biochemical marker of myocardial injury with a high level of specificity and sensitivity. It has been demonstrated that as ischaemia progresses, troponin I is degraded predictably into smaller and smaller fragments that can be detected in the blood-stream. This may eventually allow more accurate determination of the duration of ischaemia and the likelihood of myocardial salvage and recovery.