Does Coronary Collateral Circulation Mask the Presence of a Wellens Sign in Patients With Critical Stenosis of the Left Anterior Descending Artery?

Introduction Electrocardiograms are an inexpensive and indispensible tool to assess cardiac rhythm and ischemia. A Wellens sign on an EKG is either a deeply inverted (Type 1) or biphasic (Type 2) t-wave in precordial leads V2-V3 (but may extend to other precordial leads). It is associated with critical stenosis of the proximal left anterior descending (LAD) artery. Patients with a Wellens sign are at high risk for extensive anterior wall myocardial infarction as the LAD is the main coronary artery that supplies the left ventricle. Exercise stress testing is contraindicated in this patient population. In addition, appropriate management of these patients is crucial to avoid acute myocardial infarction.

There have been a number of studies addressing the role of collateral coronary circulation in myocardial infarctions. Some studies show that the presence of collateral circulation is associated with improved in-hospital outcomes in patients following a ST-elevation myocardial infarction (STEMI) whereas others show that collateral circulation does not decrease morbidity and mortality in patients following acute STEMI. Similarly, patients with collateral circulation may have normal EKGs and be asymptomatic at rest but are symptomatic with corresponding abnormal EKG findings during periods of increased cardiac demand.

Patients with a critically stenosed LAD may be asymptomatic and have normal to minimally elevated cardiac enzymes at the time of presentation with at rest abnormal EKG findings being the sole clue to the patient's gravity. While some studies have shown collateral coronary circulation lead to normal EKGs, there is limited research addressing whether or not collateral circulation affects the presence of a Wellens sign. As a result, its diagnostic utility is questionable.

Overall Aim Coronary artery disease significantly contributes to morbidity and mortality in the United States. Atherosclerotic disease can lead to stenosis of the coronary arteries and subsequent cardiac hypoperfusion. Patients with a critical stenosis of the LAD, potentially leading to acute anterior wall myocardial infarction, may be asymptomatic at presentation with subtle EKG changes as its only manifestation. It is imperative for physicians to recognize patients with new T wave inversions in leads V2-V3 as the standard course of management may lead to poor prognosis.

The purpose of this study is to determine if collateral circulation to the left anterior descending (LAD) artery will mask the presence of a Wellens sign and therefore diminish its diagnostic utility. The conclusion of this study would raise awareness for physicians in light of an absent Wellens sign.