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Applications of Lead aVR

Applications of Lead aVR. ECG Rounds February 15, 2007 James Huffman, PGY-1. Outline. Background Discussion and Practice LMCA occlusion Acute Pericarditis TCA Cardiotoxicity Preexcitation syndrome tachycardia Review. Background on lead aVR. Augmented unipolar limb lead

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Applications of Lead aVR

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  1. Applications of Lead aVR ECG Rounds February 15, 2007 James Huffman, PGY-1

  2. Outline • Background • Discussion and Practice • LMCA occlusion • Acute Pericarditis • TCA Cardiotoxicity • Preexcitation syndrome tachycardia • Review

  3. Background on lead aVR • Augmented unipolar limb lead • Placed on the lateral aspect of the R arm • Examines R upper portion of the heart (includes RV outflow tract and basal septum) • Largely ignored or used to confirm correct placement of other leads (Gorgels, 2001)

  4. Case 1 58M with RSCP. • Onset while walking into work from car • Pressure • Radiates to jaw and L arm PMHx: • MI (2001), DM-2, HTN, High Cholesterol

  5. Case 1

  6. Case 1 • Diagnosis? • ST Elevation ACS • Territory? • Anterior wall • Vessel(s)? • Left main coronary artery (wait and see)

  7. Application 1ACS from left main coronary artery obstruction • Certain obstruction patterns require mechanical reperfusion strategies (CABG or PCI) • Currently LMCA obstruction and tripple-vessel disease are contraindications for PCI • Thus, ability to differentiate LMCA obstruction has important management implications (i.e. no Plavix/no cath-lab)

  8. Application 1ACS from left main coronary artery obstruction • Several studies have examined the relationship of ST↑ in aVR with LMCA obstruction:

  9. Application 1ACS from left main coronary artery obstruction • Rostoff (2005) found 0.5mm ST↑ twice as likely in pts with LMCA obstruction (69.6% vs. 34.6%) • Kosuge found ST↑ the strongest predictor of LMCA or 3-vessel disease. Also, only ST↑ in aVR (>0.5mm) and ↑TnT were independent predictors of adverse clinical events at 90d (OR 13.8 and 7.9 respectively) • Barrabes (2003) found that in hosp. mortality increased with increasing ST↑ (1.3% if 0mm, 8.6% if 0.5-1mm and 19.4% if >1mm)

  10. Case 2 27M with pleuritic chest pain • Started 2 days ago • Worse when supine and with UL movement • No tenderness • No associated symptoms PMHx: • Occasional URTI

  11. Case 2

  12. Application 2Acute Pericarditis ECG changes classically divided into four stages: • Diffuse ST↑ (concave up) in almost all leads with reciprocal ST↓ in aVR • ST segs return to baseline, flattening of T-waves • T-wave inversion • Resolution of all previous changes

  13. Application 2Acute Pericarditis • Pts do not necessarily progress through these stages at all, let alone in an orderly fashion • PR segment depression not traditionally included in these stages but found to be of diagnostic significance by Spodick (1973) • Numerous case studies demonstrate a potential role for PR elevation in aVR for diagnosis of acute pericarditis • Only one study (50 pts) has formally examined aVR PR elevation (present in 82%, similar to ST↑)

  14. Case 3 38F found down in apartment by friend • Last seen normal 4h prior ago • Lethargic (GCS 12-13) • Anticholinergic toxidrome PMHx: • Depression, several previous suicide attempts

  15. Case 3

  16. Application 3Tricyclic Antidepressant Ingestion • Often non-specific presentation of altered mental status and an anticholinergic toxidrome • ECG changes typically precede clinically apparent neurological and cardiac toxicity • ECG can demonstrate sinus tach with QRS widening, a deep S-wave in lead I, a rightward axis and a characteristic R-wave in aVR

  17. Application 3Tricyclic Antidepressant Ingestion Changes specific to aVR: • Increased amplitude of the terminal R-wave (>3mm) • Only ECG variable to reliably predict seizure or arrhythmia (Liebelt 1995) • Increased R-wave to S-wave ratio (>1.0)

  18. Case 4 17M with syncopal episode • Occurred 1h after basketball practice • Has had “dizziness” several times before PMHx: Nil O/E: HR 270, otherwise normal

  19. Case 4

  20. Case 4

  21. Application 4Pre-excitation syndrome related narrow complex tachycardia • Several case studies have proposed a role for using ST↑ in lead aVR to differentiate AVNRT from AVRT • One study (Ho et al, 2003) examined 338 pts with narrow-complex tachycardia • AVRT was differentiated from AVNRT with a sens of 71% and a spec of 70%

  22. Take-Home Points • ACS ST↑ in aVR of > 0.5mm is reasonably sensitive and specific for LM disease • Management implications (surgery) • Prognostic implications

  23. Take-Home Points • Acute Pericarditis PR elevation in aVR may be a clue to the diagnosis

  24. Take-Home Points • TCA toxicity An R-wave >3mm in aVR is as sensitive as a QRS wider than 100ms for both seizures and arrhythmias

  25. Take-Home Points • Preexcitation syndrome related narrow-complex tachycardia ST↑ in aVR provides a clue to differentiate AVNRT from AVRT

  26. References Barrabes, JA., et al. 2003. Prognostic value of lead aVR in patients with a first non-ST segment elevation acute myocardial infaction. Circulation. 108:814-9 Gorgels, AP., et al. 2001. Lead aVR, a mostly ignored but very valuable lead in clinical electrocardiography. J Am Coll Cardiol. 38:1355-6. Ho, YL., et al. 2003. Usefulness of ST-segment elevation in lead aVR during tachycardia for determining the mechanismof narrow QRS complex tachycardia. Am J Cardiol. 92:1424-8. Kosuge, M., et al. 2005. Predictors of left main or three-vessel disease in patients who have acute coronary syndromes with non-ST segment elevation. Am J Cardiol. 95:1366-9. Kosuge, M., et al. 2006. Combined prognostic utility of ST segment in lead aVR and troponin T on admission in non-ST-segment elevation acute coronary syndromes. Am J Cardiol. 97:334-9. Liebelt, EL., et al. 1995. ECG lead aVR versus QRS interval in predicting seizures and arrhythmias in acute tricyclic antidepressant toxicity. Ann Emerg Med. 26:195-201. Rostoff, P., et al. 2005. Value of lead aVR in the detection of significant left main coronary artery stenosis in acute coronary syndrome. Kardiol Pol. 62:128-37. Spodick, DH. 1973. Diagnostic electrocardiographic sequences in acute pericarditis. Significance of PR segment and PR vector changes. Circulation. 48:575-80. Yamaji, H., et al. 2001. Prediction of acute left main coronary artery obstruction by 12-lead electrocardiography. ST segment elevation in lead aVRwith less ST segment elevation in lead V(1). J Am Coll Cardiol. 38:1348-54.

  27. Questions?

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