Myoglobin and CK-MB provided the highest positive likelihood ratios for AMI within 2 hours of ED presentation, whereas cardiac troponins were beneficial for identifying AMI ≥ 6 hours after presentation.
Cohort (n=177)
No
Do cardiac troponin I and troponin T offer better early diagnostic efficiency for acute myocardial infarction compared to CK, CK-MB, and myoglobin in ED chest pain patients without ST-elevation?
Myoglobin and CK-MB are superior to cardiac troponins for the early (≤ 2 hours) screening of acute myocardial infarction in ED patients without ST-elevation, whereas troponins become beneficial ≥ 6 hours after presentation.
OBJECTIVE: To compare the early diagnostic efficiency of the cardiac troponin I (cTn-I) level with that of the cardiac troponin T (cTn-T) level, as well as the creatine kinase (CK), CK-MB, and myoglobin levels, for acute myocardial infarction (AMI) in patients without an initially diagnostic ECG presenting to the ED within 24 hours of the onset of their symptoms. METHODS: A prospective, observational, cohort study was performed involving chest pain patients admitted to a large urban community hospital. Participants were consecutive consenting ED chest pain patients > or = 30 years of age. Exclusions included duration of symptoms > 24 hours, inability to complete data collection, receipt of CPR, and ST-segment elevation on the initial ECG. Measurements included levels of cTn-I, cTn-T, CK, CK-MB, and myoglobin at the time of presentation and 1, 2, 6, and 12-24 hours after presentation as well as presenting ECG and clinical follow-up. Confirmation of the diagnosis of AMI was based on World Health Organization criteria. RESULTS: Of the 177 patients included in the study, 27 (15%) were diagnosed as having AMIs. The sensitivities of all 5 biochemical markers for AMI were poor at the time of ED presentation (3.7-33.3%) but rose significantly over the study period. The sensitivity of cTn-T was significantly better than that of cTn-I over the initial 2 hours, but both markers' sensitivities were low ( or = 6 hours after presentation.
Tucker et al. (1997) conducted a cohort in Acute myocardial infarction (n=177). Cardiac troponin I and troponin T vs. CK, CK-MB, and myoglobin was evaluated on Early diagnostic efficiency for acute myocardial infarction. Myoglobin and CK-MB provided the highest positive likelihood ratios for AMI within 2 hours of ED presentation, whereas cardiac troponins were beneficial for identifying AMI ≥ 6 hours after presentation.