Safe discharge from the cardiac emergency room with a rapid rule-out myocardial infarction protocol using serial CK-MBmass

OBJECTIVE To determine whether a new protocol, using a rapid and sensitive CK-MBmass assay and serial sampling, can rule out myocardial infarction in patients with chest pain and decrease their length of stay in the cardiac emergency room without increasing risk. DESIGN The combined incidence of cardiac death and acute myocardial infarction at 30 days, six months, and 24 months of follow up were compared between patients discharged home from the cardiac emergency room after ruling out myocardial infarction with a CK-MBactivity assay in 1994 and those discharged home after a rapid CK-MBmass assay in 1996. SETTING Cardiac emergency room of a large university hospital. PATIENTS In 1994 and 1996, 230 and 423 chest pain patients, respectively, were discharged home from the cardiac emergency room with a normal CK-MB and an uneventful observation period. RESULTS The median length of stay in the cardiac emergency room was significantly reduced, from 16.0 hours in 1994 to 9.0 hours in 1996 (p