The following sequence of ECGs is taken from a middle-aged patient presenting with chest pain and diaphoresis. Can you interpret each ECG tracing in the context of the patient’s symptoms?


ECG 5a – Chest pain and diaphoresis (time = zero)

TOP 100 ECG QUIZ LITFL 005 1
ECG ANSWER and INTERPRETATION

This ECG demonstrates an evolving anterolateral STEMI:

  • ST elevation in V2-5 and aVL
  • Reciprocal ST depression in III and aVF
  • Pathological Q waves in V2-3
  • Hyperacute T waves in V2-4 and I

ECG 5b – Resolution of chest pain (t+20 mins)

TOP 100 ECG QUIZ LITFL 005 2b
ECG ANSWER and INTERPRETATION

There is transient improvement in the ST changes, with development of biphasic T waves in V2-3.

This pattern of T wave changes in V2-3 is known as Wellens syndrome and indicates reperfusion of a previously occluded LAD artery.

The implication of this ECG pattern is that there is an underlying critical LAD stenosis that requires emergent reperfusion, ideally via percutaneous coronary intervention.


ECG 5c – Recurrence of chest pain (t+25 mins)

TOP 100 ECG QUIZ LITFL 005 3
ECG ANSWER and INTERPRETATION

The previously biphasic T waves are now upright again — this phenomenon is referred to as pseudonormalisation and is a marker of re-occlusion of the culprit artery.

Despite temporary restoration of blood flow in ECG 5b, the patient is now re-infarcting!


ECG 5d – Ongoing chest pain and diaphoresis (t+35 mins)

TOP 100 ECG QUIZ LITFL 005 4
ECG ANSWER and INTERPRETATION

This ECG demonstrates a frank anterolateral STEMI with evolving ST changes.

This patient had a VF arrest shortly after this ECG was taken, was placed on a mechanical CPR device and taken immediately to the cath lab where she was found to have a 100% proximal LAD occlusion. She was stented, successfully cardioverted and made a good neurological recovery.


CLINICAL PEARLS

There are two patterns of T-wave abnormality seen in Wellens syndrome:

  • Type A – Biphasic, with initial positivity and terminal negativity (25% of cases)
  • Type B – Deeply and symmetrically inverted (75% of cases)

These changes evolve with time after reperfusion. The type A pattern is most commonly seen in patients with spontaneous reperfusion of an occluded LAD, as was the case above.



TOP 100 ECG SERIES


Emergency Physician in Prehospital and Retrieval Medicine in Sydney, Australia. He has a passion for ECG interpretation and medical education | ECG Library |

MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner

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