Cardiac troponin, CK-MB and myoglobin for the early detection of acute myocardial infarction and monitoring of reperfusion following thrombolytic therapy

It is important to establish as soon as possible whether patients who present with chest pain are having an acute myocardial infarction (AMI). Ideally, sensitive and specific serum myocardial markers could provide the basis for early detection as well as determine the status of reperfusion following thrombolytic therapy. The present study examined the utility of cardiac troponin I (cTnI), CK-MB, and myoglobin for the sensitive and specific detection of AMI in 98 consecutive patients presenting to the emergency department (ED) with chest pain. In addition, cardiac troponin T (cTnT), CK-MB, and myoglobin samples were measured over a 90 min time period following thrombolytic therapy in nine separate AMI patients to assess reperfusion. In the ED study, CK-MB, myoglobin, and cTnI were equally sensitive (100%) for the detection of AMI in patients who presented 7.4-14 h after onset of chest pain. However, cTnI was the most specific serum marker (specificity 91.9% compared to CK-MB 85.6%, myoglobin 61.4%). Five of the six non-related AMI patients who had an elevated cTnI had clinically documented myocardial involvement. In the reperfusion study, cTnT, CK-MB and myoglobin, relative increases were greater in reperfused compared to non-reperfused patients. Within the reperfused group, the relative increase of cTnT was greater than CK-MB and myoglobin at 90 min following thrombolytic therapy. These findings show the clinical utility of cardiac-specific troponins as markers for the early detection of AMI and monitoring of reperfusion following thrombolytic therapy.