Wellens' Pattern: A Critical Sign of Proximal Left Anterior Descending Artery Stenosis
Wellens' pattern on ECG is highly suggestive of critical stenosis of the proximal left anterior descending (LAD) coronary artery and represents a pre-infarction state that can rapidly progress to extensive anterior wall myocardial infarction if not promptly addressed. 1, 2
Characteristic ECG Findings
Wellens' pattern consists of two types of T-wave abnormalities in the precordial leads (primarily V2-V3):
These ECG changes are typically present during pain-free periods after episodes of angina 3, 5
The pattern is most commonly seen in leads V2-V3 but may extend to V1-V4 or even V1-V5 2, 5
Clinical Significance
Wellens' pattern is associated with a critical stenosis of the LAD coronary artery, classically in the proximal segment but can sometimes be found with mid-LAD lesions 2, 3
Without intervention, approximately 75% of patients with this ECG finding will develop an extensive anterior wall myocardial infarction within one week 6
Deep symmetrical T-wave inversion across the precordial leads (Wellens' phenomenon) indicates a critical stenosis of the LAD coronary artery as noted by the American Heart Association 1
Diagnostic Approach
When Wellens' pattern is identified, cardiac biomarkers may initially be normal or only minimally elevated as the pattern often appears during pain-free periods 3, 5
Serial ECGs are crucial for identifying the evolution from the subtle Type A pattern to the more obvious Type B pattern 4
Exercise stress testing is contraindicated in suspected Wellens' syndrome as it may precipitate complete occlusion of the critically stenosed LAD and lead to acute anterior wall myocardial infarction 6
Management
Urgent coronary angiography is indicated when Wellens' pattern is identified, even if the patient is pain-free and cardiac biomarkers are negative 2, 3
Early revascularization (either percutaneous coronary intervention or coronary artery bypass grafting, depending on coronary anatomy) is necessary to prevent progression to myocardial infarction 5
Medical therapy alone is generally insufficient for preventing adverse outcomes in true Wellens' syndrome with critical LAD stenosis 3
Clinical Pearls and Pitfalls
Wellens' pattern can be easily missed if ECGs are not obtained during pain-free periods or if subtle Type A changes are not recognized 4
The pattern may be mistaken for non-specific T-wave changes or attributed to other causes of T-wave inversion 7
Wellens' syndrome should be considered in any patient with a history of recent angina who presents with characteristic T-wave changes in the precordial leads, even if currently asymptomatic 3, 5
The presence of Wellens' pattern warrants immediate cardiology consultation, as delay in recognition and intervention can lead to extensive anterior myocardial infarction with significant morbidity and mortality 2, 6