[Differences in diagnostic criteria for acute myocardial ischemia at Norwegian hospitals]

In the present study medical departments at 57 (83%) of all hospitals in Norway answered a questionnaire about the criteria used to diagnose acute myocardial infarction. One hospital specified a period of chest pain lasting over 30 minutes; 14 hospitals worked on 30 minutes and 36 hospitals based their diagnosis on a period of less than 30 minutes. Six hospitals did not use any particular duration of pain in order to make a positive diagnosis. There were no important differences over the electrocardiogram criteria. Information on the type of enzymes used for diagnosis, enzyme combinations, and threshold values of the different enzymes, did reveal inequalities between the hospitals. In the 46 hospitals using creatine kinase (CK) the threshold for a positive diagnosis varied between 170 and 500 IE/1 for men and 150 and 400 IE/I for women. For aspartate dehydrogenase (ASAT) the variation was between 40 and 100 and 35 and 75 IE/I for men and women respectively. Unequal criteria for the diagnosis of acute myocardial infarction may lead to differences in treatment, variations in the assessment made by the health insurance scheme and could complicate follow-up studies of this disease.