Use of the initial electrocardiogram to predict in-hospital complications of acute myocardial infarction.

We evaluated the initial electrocardiogram as a predictor of complications in 469 patients with suspected acute myocardial infarction. An electrocardiogram was classified as positive if it showed one or more of the following: evidence of infarction, ischemia, or strain; left ventricular hypertrophy; left bundle-branch block; or paced rhythm. Forty-two (14 per cent) of 302 patients with positive electrocardiograms had at least one life-threatening complication (ventricular fibrillation, sustained ventricular tachycardia, or heart block), as compared with 1 (0.6 per cent) of 167 patients with a negative electrocardiogram. Life-threatening complications were therefore 23 times more likely if the initial electrocardiogram was positive (P less than 0.001). Other complications were 3 to 10 times more likely (P less than 0.01), interventions were 4 to 10 times more likely (P less than 0.05), and death was 17 times more likely (P less than 0.001) in patients with a positive electrocardiogram. We conclude that patients with a negative initial electrocardiogram have a low likelihood of complications and could be admitted to an intermediate care unit instead of a coronary care unit. This would reduce admissions to the coronary care unit by 36 per cent and thereby save considerable hospital costs without compromising patient care.