aVR: The Forgotten 12th Lead

Image from PMID: 22412103

Augmented leads (aVR, aVF, and aVL) were developed to derive more localized information looking at the right, lower, and left part of the heart respectively.  Specifically, lead aVR obtains information from the right upper side of the heart.  Lead aVR also gives reciprocal information from the left lateral side of the heart, which is already covered by leads aVL, I, II, V5, and V6.  This is the main reason lead aVR has become forgotten.

What is the sensitivity and specificity of lead aVR for left main coronary artery (LMCA) occlusion?
  • Yamaji et al (2001): aVR ST segment elevation (>0.05 mV) greater than ST segment elevation of V1 = sensitivity 81% and specificity of 80%
  • Rostoff et al (2006): aVR ST segment elevation (>0.05 mV) = sensitivity 68.2% and specificity 73.3%
  • Kosuge et al (2011): aVR ST segment elevation (>0.05 mV) = sensitivity 91% and specificity 79%
  • Kosuge et al (2011): aVR ST segment elevation (>0.1 mV) = sensitivity 80% and specificity 93%
  • Kosuge et al (2011): aVR ST segment elevation (>0.15mV) = sensitivity 27% and specificity 98%
Conclusion: ST elevation of >0.05 mV in aVR has a SENSITIVITY 68.2% - 91% and SPECIFICITY 73.3% - 80%

Does ST elevation in lead aVR predict clinical outcome?
  • Yamaji et al (2001): ST elevation of aVR (0.15 mV) predicts DEATH with 75% sensitivity and 75% specificity
  • Barrabes et al (2003): ST elevation of aVR (0.05 mV – 0.1mV) mortality 8.6% and ST elevation of aVR (>0.1 mV) mortality 19.4% versus no ST elevation of aVR mortality 1.3%
  • Abbase et al (2006): MORTALITY in ST elevation of aVR (0.05 mV) 30.2% vs no ST elevation in aVR 12.2%
Conclusion: ST elevation in lead aVR has INCREASED MORTALITY versus no ST elevation in lead aVR

What is the best management of ST elevation in lead aVR?
  • Several studies quote a 3-year mortality rate of 50% (1975 Study) for medical management and 36% (1989 Study) for PCI, stating that surgery (CABG) is the treatment of choice.
  • There are several new studies now looking at drug eluding stents (DES) as an option:

  • Currently the EXCEL (Evaluation of Xience Prime versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization) trial is underway and recruiting patients and can hopefully give us a more clear answer.

Conclusion: It is still not clear who would be best treated with PCI versus CABG in LMCA occlusion

Final Thoughts: Lead aVR is a forgotten but valuable lead that is highly predictive of LMCA occlusion and gives prognostic information.  The best management of LMCA occlusion is still unclear (PCI vs CABG).

Salim Rezaie, MD
Clinical Assistant Professor of EM and IM
University of Texas Health Science Center at San Antonio


  1. Abbase AH et al. The Significance of ST Segment Elevation in Lead aVR in Acute Anterior Myocardial Infarction. Med J Babylon2011. 8 (4): 490 – 96.
  2. Barrabes JA et al. Prognostic Value of Lead aVR in Patients With a First Non-ST Segment Elevation Acute Myocardial Infarction. Circ 2003; 108: 814 – 819. PMID:12885742
  3. Chieffo A et al. 5-Year Outcomes Following Percutaneous Coronary Intervention With Drug-Eluting Stent Implantation Versus Coronary Artery Bypass Graft for Unprotected Left Main Coronary Artery Lesions: The Milan Experience. JACC Cardiovas Interv 2010 June; 3 (6): 595 – 601. PMID: 20630452
  4. Kosuge M et al. An Early and Simple Predictor of Severe Left Main and/or Three-Vessel Disease in Patients With Non-ST Segment Elevation Acute Coronary Syndrome. Am J Cardio 2011; 107: 495 – 500. PMID: 21184992
  5. Nakamura K et al. Significance of ST-Segment Elevation in Lead aVR. Arch Intern Med 2012 Mar; 172 (5): 389. PMID: 22412103
  6. Rostoff P et al. ST Segment Elevation in Lead aVR and Coronary Artery Lesions in Patients with acute Coronary Syndrome. Kardiol Pol 2006. 64: 8 – 14. PMID: 16444621
  7. Yamaji H et al. Prediction of Acute left Main Coronary Artery Obstruction by 12-Lead Electrocardiography. JACC 2001; 38 (5): 1348 – 1354. PMID: 11691506