Winter is Coming…

ECG Exigency 015

A 54-year old man presents by private vehicle to the Emergency Department with chest discomfort he described as “heartburn.” The pain is substernal and non-radiating. He is also mildly diaphoretic. There is no history of diabetes, hypertension, high cholesterol, or coronary artery disease. On arrival he is resting comfortably, with the following vitals: heart rate 56, blood pressure 125/82, respirations 18 per minute and unlaboured, oxygen saturation 100% on room air. His ECG is shown below:

winter is coming
Q1: Describe the ECG.

  • Ectopic atrial rhythm: inverted P waves in II, III, aVF
  • Rate 75 bpm
  • Normal axis: +30 degrees, QRS complexes upright in leads I + II
  • Normal intervals
  • 1mm ST-segment elevation in aVR
  • Upsloping ST-segment depression in V2-V6
  • Tall, prominent, symmetric T waves throughout the precordial leads

Q2: What is the significance of these ECG findings?

These ST and T waves abnormalities are known as de Winter’s T-waves.

de winters t wave

de Winter’s T wave

This ECG finding:

  • Is specific for left anterior descending artery (LAD) occlusion.
  • Represents ~2% of LAD occlusions.
  • May persist until the culprit artery is opened (making it a STEMI equivalent) or may evolve into an anterior STEMI.

Q3: How would you manage this patient?

This patient needs to be managed as a STEMI with analgesia, nitrates, oxygen, aspirin, heparin and (most importantly) emergent PCI or thrombolysis!

Q4: Can you guess what happened next?

  • The patient was admitted for emergent PCI.
  • Angiography revealed a 100% mid-LAD occlusion, which was successfully stented.
  • His troponin peaked at 197 ng/mL.
  • The patient was eventually discharged with a normal ejection fraction.

Take Home Points

  • The de Winter ECG pattern is a recently-described STEMI equivalent that emergency physicians and paramedics must be aware of.
  • These patients typically have critical stenosis of the LAD requiring emergent PCI or thrombolysis.
  • Lack of familiarity with these ECG findings may lead to reluctance to activate the cath lab and unacceptable delays in reperfusion.
  • Remember that in many cases the de Winter pattern persisted until after the target artery was opened. Don’t wait for serial ECGs to evolve into a more easily-recognisable STEMI pattern (which may never happen): activate the cath lab now!

Learn More About De Winter’s T Waves

  • Read the de Winter page from the LITFL ECG library for more detailed information on this topic, including more fantastic ECG examples, references from the literature and links to high-quality FOAMed resources!

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  1. Kristin Boyle says

    Thanks for sharing, will add it to the bank. Is it just me or is there also some subtle ST depression in inferior leads?

  2. says

    You’re right Kristin. There is some subtle ST depression in III & aVF, which is reciprocal to the subtle ST elevation in aVL. ST elevation in aVL in the context of anterior ischaemia/infarction indicates an occlusion proximal to the first diagonal branch (D1) of the LAD, i.e. a very proximal LAD lesion.

    • says

      Hi ‘elboghdadly’
      As you point out there is no good evidence that oxygen administration is beneficial in this setting, and may (potentially) cause harm
      In practice O2 is often given to patients with active chest pain in the setting of ischemia
      Any increase in O2 delivery will be minimal and there may be harm (e.g. oxidative injury, vasoconstriction, etc) -- we don’t really know the answer yet
      I personally prefer to limit oxygen administration unless it makes the patient feel better or I think pre-oxygenation for impending intubation is warranted

  3. P M Haridas says

    Dear Mat,
    If De Winters T wave pattern seen only in V1-V3, not in the lateral leads, Do you still consider it as a LAD occlusion?

  4. nerdymedic says

    The De Winter pattern has been associated with LAD occlusion in all the publications and case studies that have described it to date. Variations in the area of infarct, I think, are likely due to variations in vasculature (eg collateral flow, etc).

  5. Edward Burns says

    Hi Kariem,
    I agree with Chris. There has been a definite move in the past few years towards rationalising oxygen therapy in conditions such as post-cardiac arrest syndrome, brain injury and acute coronary syndromes.
    The 2010 ILCOR guidelines on acute coronary syndromes make the following recommendations:

    “There is insufficient evidence to support or refute the empirical use of high-flow oxygen therapy in patients with uncomplicated AMI without signs of hypoxaemia and/or heart failure. There are insufficient data to support or refute the fact that high-flow oxygen therapy might be harmful in this setting. In addition, there is lack of evidence to suggest that low flow oxygen is of any benefit in patients with normal oxygen saturation levels.
    Oxygen therapy should be initiated if breathlessness, hypoxaemia, or signs of heart failure or shock are present. Noninvasive monitoring of oxygen saturation may be used to decide on the need for oxygen administration.”

    (, page 180)


  6. sam b says

    How can you be sure that it is an ectopic atrial rhythm and not just reversal of leads? I thought a positive P wave in aVr means limb lead reversal…unless you were there and saw correct lead placement?

    • Mat Goebel says

      Under normal circumstances, with correct lead placement, normal sinus rhythm with will be upright in II,III, and aVF, and inverted in aVR. A left-right limb lead reversal would completely invert lead I (P and QRS complex), and make aVR completely upright (P and QRS complex) while swapping leads II and III, but leading them both upright.

      Here we see that the P wave is inverted in II,III, and aVF, and inverted in aVR, while the QRS complexes are mostly upright in II,III,and aVF, and inverted in aVR. This indicates that the P and QRS vectors are going in opposite directions, further assuring us that this is not a lead reversal.