• The use of a 4-step algorithm in the electrocardiographic diagnosis of ST-segment elevation myocardial infarction by novice interpreters

    by Marc Colbeck. Last modified: 09/06/14

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    This study by Hartman from 2012 is a useful package of information that I often use at the end of a cardiology course as a “here’s what you do at 3 am when you can’t remember what else to do” aid.  Hartman, Baros and Brady present four simple rules that novice (and even experienced) 12 lead ECG readers can use to rule in most STEMI’s (but not to rule it out, which we can never do in the field).  The rules are:

    1. Is there STE of at least 1 to 2 mm in 2 anatomically contiguous leads?
    2. Is sum of the Q wave in lead V1/V2 + R wave in lead V5/V6 less than 35 mm?
    3. Is the QRS complex less than 0.12 second (3 mm) in width?
    4. Is there ST-segment depression present in at least 1 lead?

    If the answer to all four questions are ‘yes’, the clinician should suspect the presence of a STEMI.  If there is a ‘no’ to any question, then all that can be said is that the algorithm cannot be used to detect STEMI, and the astute clinician will revert to the history and presentation of the patient and consider the ECG to be ‘non-diagnostic’.

    Although the rules won’t detect all STEMI’s, they’ll detect most, and they are useful for novice ECG readers who want a simple, validated way to catch most of the ‘bread-and-butter’ STEMI’s we’ll see clinically.  The rules won’t help localize the lesion(s), but if you haven’t had the opportunity to study 12 leads in depth yet and you want a method to help determine when a STEMI is present to pre-alert the receiving hospital, this is a good start to get you going.

     
    Hartman SM1, Barros AJ, Brady WJ. The use of a 4-step algorithm in the electrocardiographic diagnosis of ST-segment elevation myocardial infarction by novice interpreters. Am J Emerg Med. 2012 Sep;30(7):1282-95. PMID: 22244224.

    Abstract

    The electrocardiographic (ECG) diagnosis of ST-segment elevation myocardial infarction (STEMI) represents a challenge to all health care providers, particularly so for the novice ECG interpreter. We have developed–and present in this article–a 4-step algorithm that will detect STEMI in most instances in the prehospital and other nonemergency department (ED) settings. The algorithm should be used in adult patients with chest pain or equivalent presentation who are suspected of STEMI. It inquires as to the presence of ST-segment elevation as well as the presence of STEMI confounding/mimicking patterns; the algorithm also makes use of reciprocal ST-segment depression as an adjunct in the ECG diagnosis of STEMI. If STEMI is detected by this algorithm, then management decisions can be made based upon this ECG diagnosis. If STEMI is not detected using this algorithm, then we can only note that STEMI is not “ruled in”; importantly, STEMI is not “ruled out.” In fact, more expert interpretation of the ECG will be possible once the patient (and/or the ECG) arrive in the ED where ECG review can be made with the more complex interpretation used by expert physician interpreters.

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    Marc Colbeck

    Marc Colbeck

    Senior Lecturer at Australian Catholic University
    Marc is a Canadian Critical Care Paramedic with 14 years of clinical experience who has been working as a professional educator since the early 2000's. He has taught at the College and University level in the Middle East and Australia, and worked as the General Manager of Clinical Governance for an Australian State Ambulance Service. He is currently a Senior Lecturer at Australian Catholic University in Queensland, Australia. His undergraduate degree is in PreHospital Care and his MA is in Counseling Psychology. He is currently working on a PhD in Translational Health Sciences with the Joanna Briggs Institute at the University of Adelaide, with a special interest in the development and maintenance of paramedic CPGs. His website is www.marccolbeck.info.

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