Computerized Electrocardiography forSelection of Patients for Prehospital

Initiated Thrombolysis

W. Douglas Weaver, MD, Peter Kudenchuck, MD, and Mary Ho, MD

Prehospital computer-interpreted electrocardio­grams (EeGs) were obtained in 1.189 patients withchest pain of suspected cardiac origin who werebeing considered for prehospital initiation of throm­bolytic therapy. Electrocardiograms were performed1.5-2 hours after the onset of symptoms. Of 391patients with evidence of acute myocardial infarc­tion, 202, or 52%, had ST-segment elevation inter­preted as acute injury by the computer algorithmcompared to 259, or 66%, by electrocardiographer.The specificity for excluding inappropriate patients

For the MIT! Project Investigators, University of Washington Schoolof Medicine, Seattle, Washington.

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was 98% and 95%, respectively. Of those patientswith acute infarction and ST-segment elevation,electrocardiographers correctly identified 92% ofcases compared to 70% sensitivity by the computer.The computer was more accurate for inferior thananterior infarction.

In summary, computer interpretive electrocar­diography can be used to select appropriate patientsfor thrombolytic therapy. Although the present al­gorithm is less than perfect at identifying all casesof ST-segment elevation, specificity is significantlyhigher than even that of the physician, thus reducingthe likelihood of inappropriate application of thistreatment.