What is the syndrome defined by a significant decrease in the ST segment in anterior leads, diagnostic of major Left Anterior Descending (LAD) coronary artery blockage?

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Last updated: April 4, 2025View editorial policy

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From the Guidelines

The syndrome defined by an extremely large decrease in the ST segment in anterior leads only, which is diagnostic of major left anterior descending (LAD) coronary artery blockage, is Wellens' syndrome. This condition is characterized by deep, symmetrical T-wave inversions or biphasic T-waves in leads V2-V3, as described in the context of acute ischemia/infarction 1. According to the standardization and interpretation of the electrocardiogram, anterior wall ischemia/infarction is invariably due to occlusion of the left anterior descending coronary artery, resulting in specific ST-segment changes in the anterior leads 1. The location of the occlusion within the left anterior descending coronary artery can be suggested by the chest leads in which the ST-segment elevation occurs and the presence of ST-segment elevation or depression in other leads 1.

Key Characteristics of Wellens' Syndrome

  • Deep, symmetrical T-wave inversions or biphasic T-waves in leads V2-V3
  • Occurs during pain-free periods in patients who have recently experienced angina
  • Indicates a critical proximal LAD stenosis (typically 90% or greater)
  • Carries a high risk of anterior wall myocardial infarction if not promptly treated

Management of Wellens' Syndrome

  • Urgent cardiac catheterization and revascularization, typically via percutaneous coronary intervention (PCI)
  • Avoidance of stress testing due to the risk of precipitating a massive anterior wall myocardial infarction
  • Recognition of this ECG pattern is crucial for identifying high-risk patients who appear clinically stable but have a severe underlying coronary lesion that could lead to extensive anterior myocardial damage if left untreated, as emphasized in the standardization and interpretation of the electrocardiogram 1.

From the Research

Definition of the Syndrome

The syndrome defined by an extremely large decrease in the ST segment in anterior leads only is known as Wellens' syndrome.

  • It is diagnostic of major LAD coronary artery blockage, as stated in the studies 2, 3, 4, 5, 6.
  • Wellens' syndrome is characterized by biphasic or deeply inverted T waves in leads V2 and V3, which is indicative of critical stenosis of the proximal left anterior descending (LAD) artery.

Electrocardiographic Findings

  • The electrocardiographic findings of Wellens' syndrome include biphasic or deeply inverted T waves in anterior precordial leads, specifically in leads V2-V6 3, 4, 6.
  • These findings are associated with significant stenosis of the proximal LAD coronary artery, which can progress to an extensive anterior myocardial infarction if left untreated 2, 5.

Clinical Significance

  • Wellens' syndrome is a precordial lead disease with T wave abnormalities that present with critical stenosis of not only the LAD but also the RCA and circumflex artery 3.
  • The diagnosis of severe stenosis of the LAD coronary artery can be made by using electrocardiographic changes in Wellens' syndrome, and patients who exhibit symptoms and test results suggestive of this syndrome should be referred for an angiographic exploration to confirm the diagnosis and guide treatment 2.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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