Computerized electrocardiography for selection of patients for prehospital initiated thrombolysis

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.

1

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.