What are the defining criteria for a Wellens ECG (electrocardiogram) pattern?

Defining Criteria for Wellens ECG Pattern

The defining criteria for Wellens syndrome include deeply inverted T waves (>0.5 mV) or biphasic T waves in leads V2-V4, often with significant QT prolongation, occurring after an episode of chest pain but without further ECG evidence of evolving infarction or ongoing ischemia. 1

Key Diagnostic Features

Essential Criteria

• T wave abnormalities in precordial leads V2-V4 (may extend to V5):
  • Type A: Biphasic T waves (initial positivity and terminal negativity)
  • Type B: Deeply inverted T waves (>0.5 mV or 5 mm)
• Significant QT prolongation
• History of recent anginal chest pain that has resolved
• Absence of pathological Q waves
• Minimal or no ST-segment elevation (<1 mm)
• Normal or minimally elevated cardiac enzymes
• Preserved precordial R wave progression

Clinical Significance

Wellens pattern is highly specific for critical stenosis of the proximal or mid left anterior descending (LAD) coronary artery 2, 3. This pattern represents a pre-infarction state that can progress to extensive anterior wall myocardial infarction if not promptly addressed 4.

Pattern Recognition Algorithm

1. Identify characteristic T wave changes:

   • Look for biphasic T waves (Type A) in leads V2-V3
   • Or deeply inverted T waves (Type B) in leads V2-V4

2. Confirm additional ECG features:

   • QT prolongation
   • Minimal or no ST elevation
   • No pathological Q waves
   • Normal precordial R wave progression

3. Correlate with clinical presentation:

   • Recent history of chest pain that has resolved
   • Minimal or no cardiac enzyme elevation

Clinical Implications and Management

Recognizing Wellens syndrome is critical as it represents a medical emergency. According to AHA/ACCF/HRS guidelines, this specific pattern should be interpreted as consistent with severe stenosis of the proximal left anterior descending coronary artery 1.

Patients with Wellens pattern require urgent cardiac catheterization as the definitive treatment 5, 4. Medical management alone is insufficient as these patients have a high risk of developing extensive anterior myocardial infarction with marked left ventricular dysfunction and death if coronary revascularization is not performed promptly 5.

Important Caveats

• The pattern may be present only when the patient is pain-free; during chest pain episodes, the ECG may show different patterns including ST elevation
• Similar T wave inversions can occur with intracranial hemorrhage (cerebrovascular accident pattern) or certain cardiomyopathies 1
• While classically associated with proximal LAD stenosis, variants have been reported with mid-LAD 2 or even circumflex artery occlusion 5
• HIV-infected patients are at higher risk for cardiovascular disease and may present with Wellens syndrome 6

Early recognition of Wellens syndrome is crucial as it allows for timely intervention to prevent massive myocardial infarction and potentially death. The characteristic ECG pattern serves as a warning sign of impending infarction that should never be overlooked.