An article by Anton P.M. Gorgels, MD, PhD, FESC, from sciencedirect.com. Please note the downloadable pdf of the full article below.

Abstract: The 12 lead surface electrocardiogram (ECG) is an indispensable tool to identify acute coronary syndromes and the patient at high risk. Acute coronary syndromes are classified according to the presence or absence of ST elevation (ST Elevation Myocardial Infarction or Acute Coronary Syndrome, STEMI or STEACS and Non ST Elevation Myocardial Infarction). NonSTEMI or nonSTEACS is approached by less invasive and frequently delayed treatment strategies. Because also nonSTEACS comprises severe and/or extensive coronary artery disease undertreatment may occur of these patient categories. Therefore better identification of those patients is needed. In the current guidelines the ischemic ECG changes are incompletely described. Improved description and understanding of the ECG in ACS will lead to better recognition of the patient at risk by emergency physicians and cardiologists.

Introduction

The 12 lead surface electrocardiogram (ECG) is an indispensable tool to identify acute coronary syndromes and the patient at high risk. Acute coronary syndromes are classified according to the presence or absence of ST elevation (ST Elevation Myocardial Infarction or Acute Coronary Syndrome, STEMI or STEACS1–4 and Non ST Elevation Myocardial Infarction). NonSTEMI or non- STEACS is approached by less invasive and frequently delayed treatment strategies. 5 Because also nonSTEACS comprises severe and/or extensive coronary artery disease undertreatment may occur of these patient categories. Mortality rates at 6 months account for 9% which is high if compared with 12% rate in STEMI.6 Therefore better identification of those patients is needed. In the current guidelines the ischemic ECG changes are incompletely described. Improved description and understanding of the ECG in ACS will lead to better recognition of the patient at risk by emergency physicians and cardiologists.

ECG changes in acute coronary syndromes

The ECG in STEACS typically display ST elevation in the precordial leads, in at least V2 and V3 in anterior wall ischemia, ST elevation in the leads II, III and aVF in inferior wall ischemia and ST elevation in the leads I, aVL and V5 and V6 in lateral wall ischemia.

The spectrum of electrocardiographic changes in non- STEACS comprises:

  1. ST depression, such as in left main stem and/or 3 vessel disease 7 and circumflex branch occlusion,
  2. No ST changes may occur, due to different possible mechanisms, to be discussed below.
  3. Postischemic changes: As a foot print of recent ischemia T wave polarity changes may be recorded, being negative in the leads reflecting the site of ischemia 8 and positive if ischemia occurred opposite to the positive electrodes.

Ischemic changes may also be recorded outside the ST segment and provide information about site and extent of the area at risk.

(Impending) rupture either of the free wall, the inter-ventricular septum or a papillary muscle is characterized by a clinically important, but frequently unrecognized ECG pattern, consisting of the triad:

  1. sinus tachycardia,
  2. subacute infarction as depicted by Q waves and
  3. persistent of recurring ST elevation, sometimes also outside the previously ischemic area.9

To read the full 6-page article, please download it here:

About Dave Klein

Founder of the Current ECG workshops, I'm an advanced care paramedic who lives and works in Nova Scotia. I also work in a clinical development role, and I'm the lead facilitator of an advanced care paramedic program. I have a passion for ECG interpretation and how this skill improves my ability to deliver quality patient care as a practitioner of emergency medicine.

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