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 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)

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

Case 1

Diagnosis? ST Elevation ACS Territory? Anterior wall Vessel(s)? Left main coronary artery (wait and see)

Application 1 ACS 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)

Application 1 ACS from left main coronary artery obstruction Several studies have examined the relationship of ST↑ in aVR with LMCA obstruction: Author#ptsST↑ (mm)Sens.Spec. Yamaji/ %80% Kosuge/ %86%

Application 1 ACS 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)

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

Case 2

Application 2 Acute 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

Application 2 Acute 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↑)

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

Case 3

Application 3 Tricyclic 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

Application 3 Tricyclic 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)

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

Case 4

Application 4 Pre-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%

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

Take-Home Points  Acute Pericarditis PR elevation in aVR may be a clue to the diagnosis

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

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

References Barrabes, JA., et al 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 Lead aVR, a mostly ignored but very valuable lead in clinical electrocardiography. J Am Coll Cardiol. 38: Ho, YL., et al Usefulness of ST-segment elevation in lead aVR during tachycardia for determining the mechanismof narrow QRS complex tachycardia. Am J Cardiol. 92: Kosuge, M., et al Predictors of left main or three-vessel disease in patients who have acute coronary syndromes with non-ST segment elevation. Am J Cardiol. 95: Kosuge, M., et al 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: Liebelt, EL., et al ECG lead aVR versus QRS interval in predicting seizures and arrhythmias in acute tricyclic antidepressant toxicity. Ann Emerg Med. 26: Rostoff, P., et al Value of lead aVR in the detection of significant left main coronary artery stenosis in acute coronary syndrome. Kardiol Pol. 62: Spodick, DH Diagnostic electrocardiographic sequences in acute pericarditis. Significance of PR segment and PR vector changes. Circulation. 48: Yamaji, H., et al 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:

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