What are the specificity and sensitivity of the Wellens sign (electrocardiogram (ECG) sign) for left anterior descending (LAD) coronary artery stenosis?

Wellens Syndrome: Diagnostic Performance for LAD Stenosis

Wellens syndrome has extremely high sensitivity (approaching 100%) but relatively low specificity (approximately 42-85%) for detecting critical proximal LAD stenosis, making it an excellent "rule-out" test but requiring confirmatory angiography due to false positives. 1, 2, 3

Diagnostic Accuracy

Sensitivity

• Sensitivity approaches 100% for detecting critical proximal LAD stenosis when the classic ECG pattern is present 1, 2
• The pattern is highly predictive of imminent massive anterior wall myocardial infarction if left untreated 1, 4
• The high sensitivity makes this an excellent screening pattern—if present, critical LAD disease is almost certainly present 3

Specificity

• Specificity ranges from 42-85% depending on the clinical context and interpretation criteria 1, 3
• The lower specificity means false positives occur, requiring angiographic confirmation 1, 2
• Other conditions can mimic Wellens pattern, reducing specificity 2, 3

Key Diagnostic Criteria

The ECG pattern requires specific findings to maximize diagnostic accuracy:

• Deeply inverted symmetrical T waves ≥2 mm in leads V2-V4, often extending to V5-V6 1, 4, 5
• Two patterns exist: Type A (biphasic T waves) and Type B (deep symmetric inversions), with Type A potentially evolving into Type B 5, 6
• QT prolongation frequently accompanies these changes 1
• Pattern may persist even after chest pain resolves 2

Critical Clinical Context

When Sensitivity/Specificity Apply

• These test characteristics apply specifically to proximal LAD stenosis, though the pattern can occasionally occur with RCA or circumflex lesions 7
• Most commonly, critical stenosis occurs in the proximal LAD, but mid-LAD involvement has been documented 4
• The pattern can present even when patients are pain-free and cardiac biomarkers are normal or minimally elevated 2, 8

Differential Diagnosis Affecting Specificity

The following conditions can produce similar T-wave patterns, explaining the lower specificity:

• Intracranial hemorrhage (CVA pattern produces similar deep T-wave inversions with QT prolongation) 1, 2
• Takotsubo cardiomyopathy (normal coronaries on angiography, apical ballooning on echo) 1, 3
• Hypertrophic cardiomyopathy or other cardiomyopathies 2, 3
• Post-ischemic changes following resolved MI 2
• Pericarditis in some presentations 3

Clinical Implications

Management Based on Test Characteristics

• The high sensitivity mandates urgent coronary angiography within hours regardless of biomarker levels or symptom status 1, 2, 3
• Stress testing is contraindicated and dangerous—proceed directly to angiography 1, 3
• The pattern indicates a pre-infarction state with imminent risk of massive anterior wall MI 1, 4, 5

Common Pitfalls

• Do not delay intervention based on normal or minimally elevated troponins—the pattern itself indicates critical disease 2, 8
• Do not perform stress testing to "confirm" the diagnosis—this can precipitate MI 1
• Serial ECGs are essential if initial ECG is equivocal, as Type A can evolve to Type B pattern 3, 6
• Approximately 5% of patients with normal ECGs discharged from emergency departments ultimately have acute MI, emphasizing the need for clinical correlation 3