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Paramedic Interpretation of Prehospital Lead-II ST-Segments

  • Robert Hill (a1), Michael Heller (a2), Alexander Rosenau (a3), Scott Melanson (a1), David Pronchik (a1), John Patterson (a1) and H. Gulick (a4)...



To determine the reliability of ST-segment interpretation by paramedics from lead-II rhythm strips obtained in the prehospital setting.


Prospective, blinded study of 127 patients transported by an urban/rural emergency medical services system with complaints consistent with ischemic heart disease.


Emergency department physicians asked emergency medical technician-paramedics (EMT-P) via radio to evaluate ST-segments for elevation or depression and grade it as “mild,” “moderate,” or “severe.” Then, this rhythm strip was interpreted blindly by emergency physicians who also interpreted the lead-II obtained from a 12-lead electrocardiogram (ECG) obtained in the emergency department (ED). The field interpretation was compared with the subsequent readings and the final in-patient diagnosis using positive predictive value (PPV), negative predictive value (NPV), and the Kappa statistic. Markedly discrepant interpretations were analyzed separately.


Using physician interpretation as the reference standard, paramedic interpretation of the lead-II ST-segments obtained in the prehospital setting was correct (within ±1 gradation) in 113 out of 127 total cases (89%). Of 105 patients for whom final hospital diagnosis was available, the ST-segment on the rhythm strip obtained in the prehospital setting, had a positive predictive value of 74% and a negative predictive value of 85% for myocardial ischemia or myocardial infarction (MI) (p <0.001, Kappa = 0.59). Discordant interpretations between the paramedics and emergency physicians often were related to a basic misunderstanding of rhythm strip morphology.


Field interpretation of ST-segments by paramedics is fairly accurate as judged both by emergency physicians and correlation with final patient outcome, but its clinical utility is unproved. A small but clinically significant number of outliers, consisting of markedly discrepant false positives, reflects paramedic uncertainty in identifying the deviations of the ST-segment.


Corresponding author

Emergency Medicine Residency, 801 Ostrum Street, Bethlehem, PA 18015USA


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1. Gibler, WB, Aufderheide, T: Emergency Cardiac Care; Mosby-Yearbook Inc.; 1994: p 147.
2. Hargarten, KM, Aprahamian, C, Stueven, H et al. : Limitations of acute myocardial infarction and unstable angina. Ann Emerg Med 1987;16:13251329.
3. Scarlovsky, S, Davidson, E, Lewin, R et al. : Acute myocardial infarction: Significance of ECG changes during chest pain. Amer Heart J 1986;112:459462.
4. Pozen, MV, Fried, DD, Vbignt, G et al. : Studies of ambulance patients with ischemic heart disease. Amer J Public Health 1977;67:532535.
5. McGuiness, JB, Begg, TB, Semple, T: First electrocardiogram in recent myocardiac infarction. BMJ 1976;2(6033):449451.
6. Karagounis, L, Ipsen, SK, Jessop, MR: Impact of field-transmitted electrocardiograph on time to in-hospital thrombolytic therapy in acute myocardial infarction. Am Emergh Med 1990;60:786791.
7. Jacobs, , Luise, JA, Eisenscher, J: Congruency in physician-EMT assessment. Ann Emerg Med 1981;10:201208.
8. Krucoff, M, Green, C, Satler, L et al. : Noninvasive detection of coronary, artery patency using continuous ST-segment monitoring. Am J Cardiol 1986;57:910922.
9. Hog, K, Hornung, R, Howie, C et al. : Electrocardiographic prediction of coronary artery patency after thrombolytic treatment in acute myocardial infarction: Use of the ST-segment as a non-invasive marker. BMJ 1988;60:275280.
10. Gibler, W, Runyon, J, Levy, R et al. : A rapid diagnostic and treatment center for patients with chest pain in the emergency department. Ann Emerg Med 1995;25:18.
11. Fasmire, F, Smith, E: Continuous 12-lead electrocardiograph monitoring in the emergency department. Am J Emerg Med 1993;11:5460.
12. Jakobsson, J, Nyquist, O, Rehnquist, N et al. : Concise education of ambulance personnel in ECG interpretation and out of hospital defibrillation. Eur Heart J 1987;8:229333.
13. Aufderheide, T, Herdley, G, Woo, J et al. : A prospective evaluation of prehospital 12-lead ECG application in chest patient patients. J Electrocardiol 1991;24:813.


Paramedic Interpretation of Prehospital Lead-II ST-Segments

  • Robert Hill (a1), Michael Heller (a2), Alexander Rosenau (a3), Scott Melanson (a1), David Pronchik (a1), John Patterson (a1) and H. Gulick (a4)...


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