Why You Should Never Ignore the De‑Winter T‑waves — the “Hidden STEMI”

Why You Should Never Ignore the De‑Winter T‑waves — the “Hidden STEMI”

Imagine a patient with crushing chest pain, classic risk factors, but the ECG shows no ST-elevation. Instead you see up-sloping ST-segment depression and towering T-waves in the precordial leads. What do you do?
This is exactly the scenario of De-Winter T-waves — a subtle, under-recognised ECG pattern that actually signals a serious culprit artery occlusion and needs the same urgency as a classic ST-elevation myocardial infarction (STEMI).

Below we explore the incidence, research evidence, ECG features, pathophysiology, clinical significance, pitfalls and how to incorporate this into your MI-card teaching resources.


What are De-Winter T-waves?

The pattern was first described in 2008 by Robbert J. de Winter and colleagues.
Key ECG features include:

  • Up-sloping ST-segment depression (typically at the J point, often 1-3 mm) in the precordial leads (V1-V6)

  • Tall, symmetrical “hyper-acute” T-waves in the same leads

  • Absence of the classic ST-elevation in those leads (though some slight ST-elevation may appear in aVR)

  • Often poor R-wave progression and sometimes loss of normal ST-T wave morphology in V2-V4

Because it lacks the “usual” ST-elevation pattern, it is easily missed — yet functionally it behaves like a STEMI, as we’ll see.


How common is it? What does the research say?

Here are some key statistics and study findings:

  • One of the earliest series found the De-Winter pattern in 30 of 1,532 patients with acute proximal left anterior descending artery (LAD) occlusion (~2.0 %) in 2008. 

  • Another study found it in 35 of 1,890 patients undergoing PCI for LAD occlusion (~1.85 %) in 2009. 

  • Broader reviews cite an incidence of approximately 2 % to 3.4 % of anterior myocardial infarctions. 

  • A recent systematic review described the De‐Winter pattern as “rare” and occurring predominantly in younger males with fewer prior coronary events. 

  • One dynamic-evolution study (18 patients) commented that all patients were male, median age ~55 yrs, and in most cases a proximal LAD occlusion or severe stenosis was found. 

Summary: While uncommon (~2 % of anterior MI presentations), the pattern is well-documented and consistently associated with serious coronary pathology.


Why does it matter?

  • The De-Winter ECG pattern is considered a STEMI-equivalent — meaning urgent reperfusion treatment (e.g., primary PCI) is indicated despite the lack of classic ST-elevation. 

  • Many cases are proximal LAD occlusions → large myocardial territory at risk. 

  • Because the appearance is “atypical”, there is a risk of delay or mis-triage, which may worsen outcomes. 

  • A recent review emphasised this pattern as “must be recognized” for early reperfusion to reduce morbidity and mortality.


Pathophysiology – Why does the ECG look like this?

The exact mechanisms remain only partly understood, but proposed explanations include:

  • Sub-endocardial rather than full‐thickness (transmural) ischemia in the very early phase, resulting in up-sloping ST depression + peaked T-waves rather than classic ST elevation. 

  • Presence of collateral circulation or pre-conditioning that prevents full ST-elevation but still indicates high‐risk occlusion. 

  • Anatomical variants (e.g., Purkinje fibre distribution), metabolic changes (ATP-sensitive-K channel dysfunction), and delayed endocardial conduction have also been postulated.


Clinical and ECG pitfalls

  • Because we often expect ST-elevation in infarction, the absence of it may lead to complacency. De-Winter may get mis-classified as NSTEMI or non-urgent. 

  • The time window may be narrow. Some studies report that it can evolve into classic STEMI or other patterns (like Wellens’ syndrome) very quickly. 

  • Differential diagnoses: tall T-waves can be seen in hyperkalaemia, early repolarisation, benign variants; ST-depression may be seen with tachycardia, digoxin effect, etc. Context (symptoms, biomarkers, imaging) is critical.

  • Coronary angiography does not always reveal a complete LAD occlusion — sometimes subtotal stenosis or other culprit vessels (diagonals, LCx, RCA) are involved. One case reported de Winter changes in D2 branch occlusion.


Key take-home summary for your blog readers

  • The De-Winter T-wave pattern is rare but high-risk.

  • If you spot up-sloping ST-depression + tall, peaked T-waves in V2-V6 in a patient with chest pain, think proximal LAD occlusion until proven otherwise.

  • It should trigger the same urgency as STEMI: rapid activation of reperfusion pathway.

  • Because it’s easily missed, education and ECG-pattern awareness are essential — especially in paramedic, ED, and cath-lab teams.

  • Incorporate this into your myocardial infarction teaching tools as one of the “abnormal waveforms” that mimic but differ from classic ST-elevation.


Hooking into your MI-card resource

You mentioned you have a myocardial infarction “card” that covers: abnormal waveforms seen in MI – ST-elevation & depression, T-wave inversion, De-Winter T-waves, Wellens Syndrome, LBBB & RBBB.
Here’s how you might integrate De-Winter into that card:

De-Winter T-waves — 12-lead ECG pattern: up-sloping ST-depression (J-point) in precordial leads + tall, symmetrical T-waves. Occurs ~2–3 % of anterior MIs. STEMI equivalent: urgent reperfusion as for proximal LAD occlusion.
Differential: hyperkalaemia, benign early repolarisation, non-acute tall T-waves – always correlate clinically.
Pitfall: lack of ST-elevation may lead to delayed management.
Teaching tip: “If you don’t see classic ST-elevation but you see this pattern in a chest-pain patient — treat it like STEMI.”

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