From the Guidelines
ST elevation in lead aVR during stress testing is a high-risk finding that warrants immediate attention and referral for coronary angiography due to its association with significant left main coronary artery disease, severe three-vessel disease, or proximal left anterior descending artery stenosis. This finding is concerning as it suggests subendocardial ischemia affecting multiple territories simultaneously, causing a current of injury that is directed away from the affected areas and toward the aVR lead, which is positioned at the right shoulder 1. The clinical significance of ST elevation in lead aVR with stress is highlighted by its usefulness for the detection of demand ischemia during exercise and for the recognition of left main and proximal left anterior descending stenoses 1.
When observed during stress testing, the test should be terminated promptly, and the patient should be stabilized with sublingual nitroglycerin 0.4 mg as needed for chest pain, aspirin 325 mg, and consideration of beta-blockers such as metoprolol 25-50 mg orally if not contraindicated. Key points to consider in the management of patients with ST elevation in lead aVR include:
- Immediate termination of the stress test
- Administration of sublingual nitroglycerin and aspirin
- Consideration of beta-blockers if not contraindicated
- Referral for coronary angiography due to the high risk of significant coronary artery disease
- Management as a high-risk patient, even in the absence of symptoms, and not discharging without further evaluation. The mechanism behind this ECG finding involves subendocardial ischemia affecting multiple territories simultaneously, causing a current of injury that is directed away from the affected areas and toward the aVR lead, which is positioned at the right shoulder, as noted in the exercise standards for testing and training by the American Heart Association 1.
From the Research
Clinical Significance of ST Elevation in Lead aVR with Stress
- ST elevation in lead aVR is often associated with global ischemia of the myocardium and obstructive coronary artery disease (CAD) 2.
- The presence of ST elevation in lead aVR with stress can indicate severe coronary disease, including left main or proximal left anterior descending coronary artery occlusion 3, 4.
- However, studies have shown that ST elevation in lead aVR with multilead ST depression is not always associated with an acutely occluded coronary artery, and routine STEMI activation for emergent revascularization may not be warranted 4.
- ST elevation in lead aVR can also be a sign of other conditions, such as acute pulmonary embolism, and is associated with a higher risk of hospital mortality in these patients 5.
- The specificity of ST segment elevation for the corresponding area is more than 90 percent, but the significance of ST segment elevation in lead aVR can be different from other leads 6.
- In patients with acute pulmonary embolism, ST elevation in lead aVR is indicative of hemodynamic instability and can predict poor outcome, but its impact on hospital mortality disappears when the presence of shock on admission is factored in the prediction model 5.