Outcome in suspected acute myocardial infarction with normal or minimally abnormal admission electrocardiographic findings.

Seven hundred seventy-five consecutive patients with symptoms suggestive of acute myocardial infarction (AMI) who were admitted to the cardiac care unit from the emergency room were studied; 107 had normal electrocardiographic findings and 73 had only minimal nonspecific changes. AMI subsequently evolved in 11 patients (10%) with normal electrocardiographic findings and in 6 (8%) with minimal changes, compared with 245 (41%) with frankly abnormal emergency room findings. Only 1 (1%; 95% confidence limits 0.02 to 5%) and 4 (6%; 95% confidence limits 2 to 15%) of those with normal and nonspecific initial electrocardiographic findings, respectively, had a complication for which they potentially benefited from intensive care unit intervention, although many patients received prophylactic therapy. Thus, the initial emergency room electrocardiogram can effectively separate patients into high- and low-risk groups for AMI and serious complications. Admission to a monitored intermediate care ward may be an acceptable practice in patients with chest pain and a normal or minimally changed initial electrocardiogram.