ECG

#FOAMed of the Week: 5 ECG Patterns you must know via rebelem.com

REBEL-EM is a fantastic source of blogs and podcasts, helping you to stay in touch with the latest mutterings in the hallways of EM......Check it out for the proper post with all the images!

Background: The electrocardiogram (ECG) is one of the most useful diagnostic studies for identification of acute coronary syndrome (ACS) and acute myocardial infarction (AMI). The classic teaching is ST-segment elevation myocardial infarction (STEMI) is defined as symptoms consistent with acute coronary syndrome (ACS) + new ST-segment elevation at the J point in at least 2 anatomically contiguous leads of at least 2mm (0.2mV) in men or at least 1.5mm in women in leads V2 – V3 and/or at least 1mm (0.1mV) in other contiguous leads or the limb leads, in the absence of a left bundle branch block, left ventricular hypertrophy, or other non-acute MI ST-segment elevation presentations. Unfortunately, the ECG may be non-diagnostic in nearly half of all patients who initially present with AMI. There are also STEMI equivalent patterns that are caused by occlusion of the coronary arteries that place a significant portion of the left ventricle at jeopardy and result in poor outcomes. This review article focused on 5 under recognized high-risk ECG patterns in the ACS patient that result in poor outcomes including malignant dysrhythmias, higher rates of cardiogenic shock, and death.

First Diagonal Branch of the Left Anterior Descending Artery Occlusion

  • The 1st diagonal branch (D1) of the LAD supplies blood to the anterolateral wall of the left ventricle
  • Look for:
    • STE in aVL and V2
    • Upright T-waves in aVL and V2
    • ST-Depression and inverted T waves in Inferior Leads (III and aVF)
  • STE in aVL and V2 + lack of STE in other precordial leads = 89% PPV for MI of the anterior wall caused by a D1 lesion

De Winter’s T Waves

  • Concerning for proximal LAD occlusion (Present in 2% of patients)
  • Look for:
    • Upsloping ST-Depression at J Point in leads V1 – V4 without STE
    • Tall, Symmetric T-Wave in leads V1 – V4
    • STE in lead aVR +/- aVL

Left Main Coronary Artery Occlusion

  • Look for:
    • STE in lead aVR AND/OR
    • Widespread ST-Depression
  • In one study STD in leads I, II, and V4 – V6 + STE in aVR present in 90% of patients with greater than 70% stenosis of the LMCA

Wellens’ Syndrome

  • Concerning for proximal critical high grad LAD occlusion
  • Consider Wellens’ if:
    • Active (or recent) angina chest pain
    • Minimal or no cardiac biomarker elevation
    • Absence of pathologic precordial Q waves
    • Minimal or lack of STE (<1mm)
    • No loss of precordial R-wave progression
    • Characteristic T-wave abnormalities
  • Two Types of Wellens’ Syndrome:
    • Type A (25% of cases) consists of biphasic t waves
    • Type B (75% of cases) consists of deep symmetric t waves
  • Provocative Stress Testing could prove to have disastrous consequences resulting in AMI and fatal dysrhythmias
  • AMI can occur within a mean of 6 – 8.5d after admission, but a mean of 21.4d after symptoms
  • T-wave changes may be transient or resolve with medical management
  • Look for:
    • Deeply inverted T-waves in leads V1 – V4 OR
    • Biphasic T-waves in leads V1 – V4

Posterior Wall AMI

  • Concerning for occlusion of either distal left circumflex artery or PDA of right coronary artery
  • If you see STD in leads V1 – V3, the next thing to do is get a posterior ECG with leads V7 – V9 to help differentiate posterior AMI vs Anterior Ischemia
  • Look for:
    • Horizontal (flat) ST-Depression in leads V1 – V3
    • Prominent R-wave in leads V1 – V2
    • Upright T-wave in leads V1 – V3

 

Clinical Bottom Line: It is important to recognize the above 5 patterns as these are high risk ACS patients because a significant portion of the left ventricle is at jeopardy.  Only 4 of the above diagnoses require activation of the cath lab immediately and the 5th requires consultation of interventional cardiology.

Cath Lab Activation:

  • 1st Diagonal Branch of the Left Anterior Descending Artery Occlusion
  • de Winter’s T Waves
  • Left Main Coronary Artery Occlusion
  • Posterior STEMI

Interventional Cardiology Consultation:

  • Wellens’ Syndrome

#FOAMed of the Week: Modified Sgarbossa Criteria via REBEL EM

Salim Rezaie and the crew at R.E.B.E.L EM have kindly published a nice appraisal of a recent Retrospective study seeking to externally validate the Modified Sgarbossa Criteria. These rules guide interpretation of ECG ischaemia in LBBB.

This article gives a useful run down of the criteria and how to use them, as well as taking us through a critical appraisal - useful for anyone approaching FCEM. 

Check out the blog here: Modified Sgarbossa Criteria: Part Deux

#FOAMed of the Week: VT vs SVT with aberrancy AND Free ECG Book via Steve Smith's ECG Blog

Rather than a podcast or vodcast I want to highlight two amazing #FOAMed (Free Open Access Medical Education) resources in the blogosphere. 

Firsly a link to Dr Steve Smith's ECG Blog on an ECG Case looking at management of VT vs SVT with aberrancy (Classic ED ECG Dilemma).

This includes the main pitfall for the use of Adenosine in broad complex tachycardia. 

Second is to highlight his book which is available free from his website and at the link below: 

Click the pic to get access to downloadable pdf.&nbsp;

Click the pic to get access to downloadable pdf. 

Although free it is one of the highest regarded books in this area and is essential reading for ED physicians. 

Finally I also wanted to highlight that anyone looking for a summary of the SMACC Chicago Conference should check out www.heftemcast.co.uk for day by day account of the educational pearls from a UK perspective. 

Get LearnED!

 

#FOAMed of the Week: ECGs Not To Be Missed via cemfoamed.co.uk

We perform and review hundreds of ECGs a day and it can be easy to become blasé..... but our role is about spotting the needle in the haystack. 

Richard Jackson, an Advanced Nurse Practitioner in Emergency Medicine gives a great summary of some of the less obviously abnormal ECGs to look out for. 

Check cemfoamed.co.uk, for loads more UK relevant podcasts. 

Wellen's Who? De Winter What? #FOAMed of the Week from Amal Mattu

Wellens Syndrome is a frequent topic for ad-hoc teaching in our ED handovers. The following resources put some flesh on the bones of what Wellen's syndrome is and what it means. I have also included a video lesson on the less-talked-about  but possibly more important De Winter T Waves. 

The author, Dr Amal Mattu, is a Professor of Emergency Medicine in the University of Maryland school of Medicine, Baltimore, Maryland. For several years he has produced weekly ECG video lessons on his tumblr blog, but recently transferred his work across to ecgweekly.com which provides weekly lessons as a subscription service. He also has provided teaching on the brilliant subscription podcast EM RAP. 

The good news is that many of his older video lessons are still available on youtube:  https://www.youtube.com/user/umemergencymed/videos

Onto the videos!

Viva La #FOAMed

Wellens Syndome and Mimics

De Winter T Waves

BONUS: Wellens Mimic Pattern