CONTRIBUTION OF CREATINE-KINASE MB MASS CONCENTRATION AT ADMISSION TOEARLY DIAGNOSIS OF ACUTE MYOCARDIAL-INFARCTION

Objective-To assess the diagnostic value at admission of creatine kina se MB mass concentration, alone or in combination with electrocardiogr aphic changes, in suspected myocardial infarction. Design-Prospective study of all consecutive patients admitted within 12 hours after onset of chest pain to a coronary care unit for evaluation of suspected myo cardial infarction. Setting-Large regional hospital. Patients-in 297 p atients creatine kinase and creatine kinase MB activities and creatine kinase MB mass concentration were determined. Myocardial infarction a ccording to the criteria of the World Health Organisation was diagnose d in 154 patients and excluded in 143 patients (including 70 with unst able angina pectoris) . Results-Sensitivity/specificity for creatine k inase MB mass concentration in patients admitted within 4 hours and 4- 12 hours after onset of chest pain were 45%/94% and 76%/79% respective ly. Corresponding values for creatine kinase activity were 20%/89% and 59%183%, and for creatine kinase MB activity 16%/87% and 53%/87%. Rai sed creatine kinase MB mass concentration was seen in 17% of patients with unstable angina pectoris. Stepwise logistic regression analysis s howed that independent predictors of acute myocardial infarction in pa tients admitted within 4 hours after onse;t of chest pain were electro cardiographic changes and creatine kinase IMB mass concentration on ad mission; in patients admitted 4-12 hours after the onset of pain indep endent predictors were electrocardiographic changes and creatine kinas e MB mass concentration and activity. Conclusion-Creatine kinase MB ma ss concentration is a more sensitive marker for myocardial infarction than the activity of creatine kinase and its ME isoenzyme. Electrocard iographic changes on admission in combination with creatine kinase MB mass concentration (instead of creatine kinase and creatine kinase MB activities) are best in diagnosing myocardial infarction.