What does ST elevation in aVR (augmented voltage right) signify?

ST Elevation in aVR: Clinical Significance

ST elevation in lead aVR, particularly when accompanied by widespread ST depression in multiple other leads, most commonly indicates severe multivessel coronary disease or left main coronary artery obstruction and warrants urgent—though not necessarily emergent—cardiac catheterization. 1

Primary Clinical Significance

Left main or multivessel disease pattern: The presence of ST depression >0.1 mV in eight or more surface leads, coupled with ST elevation in aVR and/or V1, suggests ischemia due to multivessel or left main coronary artery obstruction, particularly when the patient presents with hemodynamic compromise. 1

Proximal LAD occlusion: ST elevation in aVR can also occur with proximal left anterior descending coronary artery occlusion above the first septal and first diagonal branches, typically accompanied by ST elevation in V1-V4, I, and aVL, with reciprocal ST depression in inferior leads. 1

Critical Nuance: The Reality vs. Guidelines

Important caveat: While the 2013 ACC/AHA STEMI guidelines endorsed ST elevation in aVR with multilead ST depression as a potential STEMI equivalent warranting emergent reperfusion 1, more recent evidence challenges this approach:

• A 2019 study of 99 patients with ST elevation in aVR and multilead ST depression found that only 10% had an acutely occluded coronary artery requiring emergent intervention, and none had left main or proximal LAD occlusions. 2
• Despite the low rate of acute occlusion, this ECG pattern was associated with 31% in-hospital mortality, indicating severe underlying disease even without acute thrombotic occlusion. 2
• The pattern is associated with severe three-vessel or multivessel disease (higher Gensini scores), reduced left ventricular ejection fraction, and increased mitral regurgitation. 3

Differential Diagnosis Beyond Coronary Disease

Non-coronary causes to consider:

• Severe anemia with demand ischemia 4
• Drug overdose causing vasospasm and tachycardia 4
• Takotsubo syndrome (though ST elevation in aVR is typically absent in this condition) 1
• De Winter pattern (0.5-1 mm ST elevation in aVR with upsloping ST depression in precordial leads) 1

Recommended Management Approach

Urgent vs. emergent catheterization decision:

1. Emergent catheterization (immediate) is indicated when:

   • Hemodynamic instability is present 1
   • Ongoing chest pain despite medical therapy 1
   • Cardiac arrest has occurred 2

2. Urgent catheterization (within hours, not minutes) is appropriate when:

   • Patient is hemodynamically stable 2
   • Symptoms have resolved with medical therapy
   • The pattern suggests severe coronary disease but not acute thrombotic occlusion 2

Initial evaluation should include:

• Assessment for non-coronary causes (anemia, drug toxicity, hemodynamic stress) 4
• Echocardiography to evaluate wall motion abnormalities, left ventricular function, and valvular disease 1, 3
• Serial troponin measurements 1

Prognostic Implications

While ST elevation in aVR with multilead ST depression does not provide independent prognostic value beyond comprehensive risk stratification using validated models like the GRACE risk score 5, it remains a marker of:

• Higher unadjusted in-hospital and 6-month mortality 5
• More extensive coronary atherosclerosis 3, 5
• Reduced left ventricular function 3

Major ST elevation (>1 mm) in aVR is an independent predictor of left main or three-vessel disease (adjusted OR 2.68), making it useful for early risk stratification. 5