Wellens Type A: Biphasic T-Waves in V2-V3
Biphasic T-waves in leads V2-V3 (Wellens type A) represent a critical pre-infarction state indicating severe proximal left anterior descending (LAD) coronary artery stenosis that requires urgent coronary angiography and revascularization to prevent massive anterior wall myocardial infarction. 1, 2
Clinical Significance and Pathophysiology
Wellens type A is characterized by biphasic T-waves (typically positive-negative deflection) in the anterior precordial leads V2-V3, often extending to V4-V6, and represents a high-risk electrocardiographic pattern associated with 75-80% proximal LAD stenosis. 3, 4, 5
This pattern occurs during pain-free periods after resolution of chest pain, making it particularly dangerous because patients appear clinically stable while harboring critical coronary stenosis. 5, 6
The American Heart Association specifically identifies deeply inverted T-waves with QT prolongation in leads V2-V4 as consistent with severe stenosis of the proximal LAD, and this guidance extends to the biphasic variant (type A). 1
Coronary angiography typically reveals 70-99% stenosis of the proximal or mid-LAD artery with preserved collateral circulation, explaining why cardiac biomarkers are often normal or only minimally elevated at presentation. 1, 3, 6
Diagnostic Criteria for Wellens Type A
- Biphasic T-waves in leads V2-V3 (and often extending through V4-V6) 3, 5
- Recent history of chest pain (within hours to days) that has now resolved 5, 6
- Normal or minimally elevated cardiac biomarkers (troponin typically normal) 3, 6
- Preserved R-wave progression (distinguishing it from prior infarction) 3
- Absence of Q-waves in precordial leads 6
- Normal or near-normal left ventricular function on initial assessment 3
Critical Distinction: Type A vs Type B
Type A Wellens (25% of cases) shows biphasic T-waves and is more subtle and frequently missed, while Type B (75% of cases) shows deeply inverted symmetrical T-waves ≥2mm in V2-V4. 5, 7
Type A is particularly challenging to recognize because the biphasic morphology can be mistaken for nonspecific T-wave changes, leading to catastrophic delays in treatment. 5
Immediate Management Protocol (First 10 Minutes)
Activate the acute coronary syndrome protocol immediately upon recognition of Wellens pattern, regardless of current symptom status or normal cardiac biomarkers. 2
Administer aspirin 162-325 mg orally (unless contraindicated) 2
Establish intravenous access and initiate continuous cardiac monitoring 2
Obtain serial cardiac troponin measurements at 0,1-2, and 3 hours (high-sensitivity preferred) 8
Administer sublingual nitroglycerin if any residual chest discomfort is present 2
Initiate dual antiplatelet therapy (aspirin plus P2Y12 inhibitor such as ticagrelor or prasugrel) 2, 3
Start anticoagulation with low-molecular-weight heparin or unfractionated heparin 8
Administer high-intensity statin therapy immediately 3
Urgent Cardiac Catheterization
Urgent (not emergent) coronary angiography should be performed within 24-72 hours, but many experts recommend proceeding within 24 hours given the high risk of progression to anterior STEMI. 2, 8
The American College of Cardiology recommends that this electrocardiographic pattern activate the acute coronary syndrome protocol equivalent to ST-elevation, despite the absence of ST-elevation. 2
Percutaneous coronary intervention with drug-eluting stent placement is the definitive treatment and has been shown to prevent anterior wall myocardial infarction in the majority of cases. 3, 4
Intravascular ultrasound during catheterization frequently reveals plaque rupture with thrombosis, confirming the unstable nature of these lesions. 3
Critical Pitfalls to Avoid
Do not perform stress testing in patients with recognized Wellens pattern, as exercise can precipitate acute LAD occlusion and massive anterior wall infarction. 6, 7
Do not discharge patients with biphasic T-waves in V2-V3 and recent chest pain based on negative initial troponin alone—this is a pre-infarction state requiring intervention. 5, 7
Do not mistake type A Wellens for nonspecific T-wave changes; the biphasic morphology in the context of recent chest pain is highly specific for critical LAD stenosis. 5
Do not delay angiography for medical optimization—revascularization is the only definitive treatment that prevents progression to infarction. 1, 7
Recognize that T-wave pseudonormalization (return to upright T-waves) can occur and represents ongoing ischemia, not improvement. 3
Differential Diagnosis to Exclude
Recent intracranial hemorrhage can produce deeply inverted T-waves with QT prolongation in similar leads, requiring neurological assessment if clinically indicated. 1
Left ventricular hypertrophy produces high-amplitude T-waves but with different morphology and clinical context. 2
Early repolarization pattern occurs in young healthy individuals but shows distinct morphological characteristics and lacks the clinical context of recent chest pain. 2
Prognosis Without Intervention
Without revascularization, 75% of patients with Wellens syndrome progress to extensive anterior wall myocardial infarction within weeks, often with devastating consequences including cardiogenic shock and death. 4, 6, 7
Medical management alone (without revascularization) is associated with high risk and poor outcomes in this population. 1, 9
Post-Intervention Management
Continue dual antiplatelet therapy for minimum 12 months post-stent placement 3
High-intensity statin therapy indefinitely 3
Beta-blocker therapy if left ventricular dysfunction is present 8
ACE inhibitor or ARB for cardioprotection 8
Cardiac rehabilitation and aggressive risk factor modification 3
Serial echocardiography to monitor left ventricular function, as early intervention typically preserves normal ejection fraction 3