Diagnostic criteria for hospitalized acute myocardial infarction: the Minnesota experience

Standardized diagnostic algorithms are needed for systematic surveillance of hospitalized acute myocardial infarction (AMI). Ambiguities in diagnostic classification are resolvable to the extent that objective information is available in the hospital chart. In this study of diagnostic algorithms, serum cardiac enzyme levels, especially creatine kinase total (CK-TOT) and creatine kinase myocardial band (CK-MB) isoenzyme, were most closely correlated with the physician-reviewer diagnostic assignment used for validation; chest pain and electrocardiographic findings were less closely correlated. In addition, a close relationship was noted between the clinician's diagnostic impression and testing procedures and the final hospital discharge diagnosis. Thus, the algorithm should include discharge diagnosis as a classification element. The algorithm for cases discharged as acute myocardial infarction should be very sensitive, tending to call cases acute myocardial infarction. Other discharge diagnoses may harbour some clinically unrecognized myocardial infarction cases; however, the algorithm for such cases should be restrictive and specific to minimize false positives. These findings indicate optimal ways of combining clinical characteristics to most completely and accurately identify cases of acute myocardial infarction based on hospital records examined in retrospect.