Wellens syndrome is a pattern of deeply inverted or biphasic T waves in V2-3, which is highly specific for a critical stenosis of the left anterior descending artery (LAD).
Patients may be pain free by the time the ECG is taken and have normally or minimally elevated cardiac enzymes; however, they are at extremely high risk for extensive anterior wall MI within the next few days to weeks.
Due to the critical LAD stenosis, these patients usually require invasive therapy; do poorly with medical management; and may suffer MI or cardiac arrest if inappropriately stress tested.
- Deeply-inverted or biphasic T waves in V2-3 (may extend to V1-6)
- Isoelectric or minimally-elevated ST segment (< 1mm)
- No precordial Q waves
- Recent history of angina
- ECG pattern present in pain-free state
- Normal or slightly elevated serum cardiac markers
Understanding The T Wave Changes
The following sequence of events is thought to occur in patients with Wellens syndrome:
- A sudden occlusion of the LAD, causing a transient anterior STEMI. The patient has chest pain & diaphoresis. This stage may not be successfully captured on an ECG recording.
- Re-perfusion of the LAD (e.g. due to spontaneous clot lysis or prehospital aspirin). The chest pain resolves. ST elevation improves and T waves become biphasic or inverted. The T wave morphology is identical to patients who reperfuse after a successful PCI.
- If the artery remains open, the T waves evolve over time from biphasic to deeply inverted.
- The coronary perfusion is unstable, however, and the LAD can re-occlude at any time. If this happens, the first sign on the ECG is an apparent normalisation of the T waves — so-called “pseudo-normalisation”. The T waves switch from biphasic/inverted to upright and prominent. This is a sign of hyperacute STEMI and is usually accompanied by recurrence of chest pain, although the ECG changes can precede the symptoms.
- If the artery remains occluded, the patient now develops an evolving anterior STEMI.
This sequence of events is not limited to the anterior leads — similar changes may be seen in the inferior or lateral leads, e.g. with RCA or circumflex occlusion.
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