Principal Findings:

AMI was diagnosed in 814 of 6,352 patients enrolled (12.8%). Patients having AMI treated with thrombolytic therapy did not differ between the stat and control groups (15.1% vs. 17.1%, P = 0.45; primary endpoint). When only patients with ST segment elevation on their initial electrocardiogram were compared, there were no significant differences between the groups (39.5% for stat vs 42.1% for control; p = 0.70). Reperfusion therapy (thrombolytic or PTCA) was also similar for the stat and control groups (58.5% vs 64.2%, p = 0.42). There was no difference in the hospital placement of patients in critical care and non--critical care beds (secondary endpoint). The availability of early markers was associated with more hospital admissions as compared to the control group, as the number of patients discharged from the ED was decreased in the stat versus control groups (28.4% vs. 31.5%, P = 0.023).

The availability of 0- and 1-h myoglobin and CK-MB results after ED evaluation had no effect on the use of thrombolytic therapy for patients presenting with AMI, but increased the number of patients admitted to the hospital without evidence of acute myocardial necrosis.