Acute analysis of myoglobin for early identification of AMI-patients without ST-elevation in the ECG to thrombolytic therapy. Clinical experiences from the EDIT-study

Purpose: In a prospective design to assess the clinical value of acute analysis of myoglobin for identification of AMI-patients presenting without ST-elevation in the ECG to thrombolytic treatment (TT). Methods: From January to December 1996 myoglobin was analysed acutely in all patients ≤, 75 years admitted at the CCU≤ 6 hours from onset of typical symptoms, who did not have contraindications to TT, provided no significant ST-elevation or new BBB was present in the ECG. Plasma was frozen at -80° C and later analysed for CK-MB mass and troponin I. All markers were analysed on the OPUS-plus system from Behring. Results: 155 patients were included in the study. 13 % had the AMI-diagnosis confirmed, 37 % suffered from acute ischemic chest pain (20 % unstable angina, 17 %stable angina), 50% from non-ischemic conditions. At a predefined cut-off value of 90 μg/l the sensitivity for diagnosis of AMI was 79 % 2-4 hours from onset of symptoms and 88% 4-6 hours from onset of symptoms. Specificity was 94% and predictive value of a negative test 97 %. The predictive value of a positive test was however only 65 %. Conclusion: myoglobin is a sensitive and fairly specific early marker of AMI identifying 88 % of AMI-patients presenting without ST-elevation in the ECG < 6 h from onset of symptoms. Due to the low AMI-prevalence of the study population, the predictive value of a positive test is however too poor to rely solely on myoglobin in the identification of AMI-suspicious patients to a potentially hazardeous treatment as TT. Supplementary early markers / methods thus are needed.