Risk stratification according to the initial electrocardiogram in patients with suspected acute myocardial infarction.

Previously developed initial electrocardiogram (ECG) prediction rules were modified to stratify 426 patients with suspected acute myocardial infarction into low-, intermediate-, and high-risk groups (normal, abnormal, and positive ECG categories) for development of acute myocardial infarction and complications of coronary ischemia. Compared with patients with normal ECGs, patients with positive ECGs had a 2.9 times greater risk of interventions, a greater risk of life-threatening complications, and a 14.2 times greater risk of acute myocardial infarction. Compared with patients with abnormal ECGs, patients with positive ECGs had a 1.7 times greater risk of interventions, a 2.6 times greater risk of life-threatening complications, and a 4.9 times greater risk of acute myocardial infarction. This prediction scheme was further improved by assigning "high" risk to any patient requiring an acute intervention during the initial evaluation in the emergency department. Otherwise, risk was assigned according to the ECG category, with normal, abnormal, and positive ECGs corresponding to "low," "intermediate," and high risk, respectively. Hospitals with limited intensive care beds may be able to use these prediction rules as an aid in determining in-hospital disposition of patients with suspected acute myocardial infarction.