T-Waves

  • Hyperacute T-waves are often the first manifestation of complete vessel occlusion; they are wide, bulky and prominent.
  • Hyperacute T-waves are not necessarily tall, and small T-waves can still be hyperacute when paired with a low-amplitude QRS complex.
  • De Winter T-waves represent LAD occlusion (a STEMI equivalent) requiring immediate revascularization.
  • Previously inverted T-waves can appear normal and upright in the setting of acute vessel occlusion. This is known as pseudonormalization.
  • The tall T-waves associated with hyperkalemia are sharp, pointy, symmetric, and have a narrow base.
  • When in doubt, get serial ECGs (every 15 minutes) and use adjunctive information.

 

Heart Blocks: A Primer

  • Heart blocks can be a sign of underlying pathology such as MI, Lyme disease, myocarditis, structural heart disease, pulmonary embolism, autoimmune disease, electrolyte disturbances, medication side effects, Lenegre’s or Lev’s disease, increased vagal tone, or could be a normal variant.
  • Treatment with Atropine is indicated in bradycardic, symptomatic and/or unstable patients with a 1st or 2nd-degree Mobitz type 1 AV block. It is unlikely to be effective in high-grade blocks as the block is usually below the AV node. Atropine can still be used as a temporizing measure while setting up for transcutaneous pacing and/or transvenous pacemaker placement in high-grade blocks
  • Take the QUIZ

 

The Heart Score

  • The risk of ACS in patients with negative biomarkers and normal ECGs approaches 0.2%.
  • Prior risk scores, such as TIMI and GRACE, provide little, if any benefit, in risk stratification for ED chest pain patients.
  • The HEART score and pathway can risk stratify patients into three separate categories: low (0-3), moderate (4-6), and high score (> 7).
  • Low-risk patients on the HEART pathway demonstrate likelihood of ACS that approaches < 1%, and it is easy to use in the ED.
  • Risk factors, history, ECG, troponin, follow up, gestalt, patients with points 3 or 4, and research design are areas of potential weakness.
  • Further improvement of the HEART pathway at this time is difficult, but in patients at moderate risk, CCTA may hold promise for evaluation of risk. This requires further study.

 

Chest Pain in Atrial Fibrillation

This is a great example of how the dichotomy between STEMI and Non-STEMI is false.  They are both due to thrombus in the coronary artery and both are very dangerous.  STEMI and NonSTEMI exist on a spectrum.  Thrombus can lyse and propagate, and NonSTEMI can convert to STEMI.

 

The STEMI ECG Assessment

This ECG assessment is designed to evaluate your ability to use simply the 12-Lead ECG to make the diagnosis of a coronary artery occlusion. It uses a standardized list of 36 ECG’s from McCabe JM, et al. Physician Accuracy in Interpreting Potential ST-Segment Elevation Myocardial Infarction Electrocardiograms. J Am Heart Assoc. 2013;2:e000268.

How to improvise ECG electrodes

In a resource limited setting, it can be fairly expensive to replenish standard, disposable electrodes used for continuous ECG monitoring.  We have found that one can effectively improvise ECG electrodes using cotton wool swabs.

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