Rapid enzyme diagnosis of patients with acute chest pain reduces patient stay in the coronary care unit.

We have studied the effect of early exclusion of myocardial infarction using rapid biochemical diagnosis on the management of patients admitted to the coronary care unit of a district general hospital. Diagnosis was based on the rate of creatine kinase increase in serial samples obtained over the 8 h following admission. For an initial 3-month familiarization period serial creatinine kinase results were made available at the end of working day to supplement clinical management, supported by our traditional protocol of admission and daily enzyme determinations. Subsequently, for a 4-month period, the admission to 8 h serial values were provided by 1100 h each day and usually within 24 h of admission. There was a net reduction in length of stay on the coronary care unit to a median 2 days (n = 66) compared with 3 days (n = 41) for patients without further cardiac symptoms or electrocardiographic changes suggestive of ischaemia or infarction. This change was significant, P = 0.007, Mann-Whitney U test. Reversion to the original protocol of daily enzyme estimations resulted in an increase in the length of stay on the coronary care unit back to a median of 3 days for this patient group. Rapid diagnostic protocols, applied within routine clinical practice, have the potential for real reduction in coronary care unit stay.

Early diagnosis of acute myocardial infarction by CK-MB mass measurements.

We have studied the changes in creatine kinase (CK) and creatine kinase MB (CK-MB) activity and concentration for the diagnosis of acute myocardial infarction in 73 patients admitted to the coronary care unit with cardiac symptoms of 12 h duration or less. Serial blood samples were obtained for an 8 h period following admission and CK, CK-MB activity and concentration measured. We compared the performance of single values at optimized diagnostic cut-offs and incremental change (log slope) for all three measurements. CK slope combined with CK-MB concentration measurements allowed accurate diagnosis at 4 h from admission. CK-MB concentration determination 8 h from admission (12-16 h from the onset of chest pain) was the most efficient single measurement. Rapid diagnostic categorization and possible selection of patients for thrombolysis in patients with an uncertain admission diagnosis is possible by these techniques.