Tia of Heart: Understanding "Wellens Syndrome" 🫀.

Dr. Zayed | Published : 19, April 2025.

Wellens Syndrome is an electrocardiographic pattern that signifies a critical stenosis of the proximal left anterior descending (LAD) coronary artery. First described in the early 1980s by de Zwaan, Wellens, and colleagues, this syndrome is observed in patients with a history of anginal chest pain who are pain-free at the time of ECG recording.

Pathophysiology of Wellens syndrome (concept of "occlusion → reperfusion → re-occlusion"): Wellens syndrome represents a critical pre-infarction state typically due to a high-grade stenosis of the proximal left anterior descending (LAD) artery. The ECG changes reflect a dynamic sequence of ischemia and reperfusion events. Initially, a sudden and complete occlusion of the LAD may cause a transient anterior STEMI, manifesting as chest pain and diaphoresis. This phase is often missed on ECG due to its brief duration. Reperfusion either spontaneous or due to interventions like prehospital aspirin or spontaneous clot lysis leads to resolution of chest pain and the emergence of biphasic or deeply inverted T waves in the anterior leads, mirroring the post-reperfusion pattern seen after successful PCI.

If coronary flow remains stable, the T waves typically evolve from biphasic to deeply inverted over time. However, the situation is often unstable, and the LAD can re-occlude unpredictably. In such cases, the ECG may show apparent normalisation of the T waves, a phenomenon referred to as "pseudo-normalisation". This transition from inverted or biphasic to upright, prominent T waves marks a critical moment. It is an early sign of hyperacute STEMI and is typically accompanied by recurrent chest pain, although the ECG change may precede symptoms.

If the artery remains occluded, the patient progresses to a full anterior STEMI. Alternatively, a “stuttering” pattern of intermittent occlusion and reperfusion may develop, leading to alternating ECG findings of Wellens T wave patterns, pseudo-normalisation, and evolving STEMI.

Importantly, while this sequence is most often associated with the anterior leads due to LAD involvement, similar T wave changes can occur in inferior or lateral leads in cases of RCA or circumflex artery occlusion!

Lastly, it's essential to recognize that Wellens syndrome is not always due to thrombotic occlusion. It can also be triggered by severe coronary vasospasm for example, following cocaine use producing a similar ECG and clinical picture. Regardless of the underlying cause, the safest clinical approach is to presume critical LAD stenosis and proceed urgently with coronary angiography to prevent progression to a large anterior myocardial infarction.

ECG Patterns in Wellens Syndrome:

Two distinct T-wave patterns are recognized:

  • Type A: Biphasic T-waves in leads V2–V3, characterized by an initial positive deflection followed by a negative deflection. This pattern accounts for approximately 25% of cases.

  • Type B: Deeply inverted, symmetrical T-waves in leads V2–V3, and sometimes extending to V1–V6. This is the more common pattern, seen in about 75% of cases. ​

These T-wave abnormalities are typically observed when the patient is asymptomatic, emphasizing the importance of serial ECGs in patients with recent chest pain.

Clinical Significance: Wellens Syndrome is crucial, as it indicates a high risk for an impending extensive anterior wall myocardial infarction. Studies have shown that without appropriate intervention, such as urgent coronary angiography and revascularization, a significant proportion of patients may progress to a large anterior MI within days.

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