Study objective: To determine the rate of missed acute myocardial infarction (AMI) in the emergency department and the factors related to missed diagnoses.
Study design: Observational and case-control study.
Setting: Data were analyzed from a multicenter study of coronary care unit admitting practices that included patients who presented to the ED with chest pain or other symptoms suggestive of acute cardiac ischemia (N = 5,773). Patients with missed AMI (cases) were compared with control patients admitted with AMI and to a second control group of patients discharged without AMI.
Results: Of 1,050 patients with AMI, 20 (1.9%; 95% confidence interval, 1.2-2.9%) were not admitted. Patients with missed AMI were significantly less likely to have ECG changes and a history of AMI or nitroglycerin use than patients admitted with AMI. However, they were significantly more likely to have ECG changes than patients discharged without AMI. Five patients with missed AMI (25%) had ST-segment elevation, and seven (35%) were discharged with a diagnosis of ischemic heart disease by the physician in the ED. Death or potentially lethal complications occurred in 25% of missed AMI patients.
Conclusion: The rate of missed AMI in the ED was only 1.9%. However, 25% of these might have been prevented had ST-elevation not been missed, and another 25% might have been prevented had patients who were recognized to have ischemic heart disease by the physician in the ED been admitted.