Applications of Lead aVR

ECG RoundsFebruary 15, 2007James Huffman, PGY-1

Outline

1. Background2. Discussion and Practice

a) LMCA occlusionb) Acute Pericarditisc) TCA Cardiotoxicityd) Preexcitation syndrome

tachycardia3. 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 carPressureRadiates to jaw and L arm

PMHx:MI (2001), DM-2, HTN, High Cholesterol

Case 1

Case 1 Diagnosis?

ST Elevation ACS

Territory?Anterior wall

Vessel(s)?Left main coronary artery (wait and see)

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)

Application 1ACS from left main coronary artery obstruction

Several studies have examined the relationship of ST↑ in aVR with LMCA obstruction:

Author #pts ST↑ (mm) Sens. Spec.

Yamaji/2001 86 0.5 81% 80%

Kosuge/2005 310 0.5 78% 86%

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)

Case 227M with pleuritic chest pain

Started 2 days agoWorse when supine and with UL movementNo tendernessNo associated symptoms

PMHx:Occasional URTI

Case 2

Application 2Acute Pericarditis

ECG changes classically divided into four stages:1. Diffuse ST↑ (concave up) in almost all leads

with reciprocal ST↓ in aVR2. ST segs return to baseline, flattening of T-

waves3. T-wave inversion4. Resolution of all previous changes

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↑)

Case 3

38F found down in apartment by friendLast seen normal 4h prior agoLethargic (GCS 12-13)Anticholinergic toxidrome

PMHx:Depression, several previous suicide

attempts

Case 3

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

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)

Case 417M with syncopal episode

Occurred 1h after basketball practiceHas had “dizziness” several times

before

PMHx: Nil

O/E: HR 270, otherwise normal

Case 4

Case 4

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 tachycardiaAVRT was differentiated from AVNRT with

a sens of 71% and a spec of 70%

Take-Home Points

1. ACSST↑ in aVR of > 0.5mm is reasonably sensitive and specific for LM disease

Management implications (surgery)

Prognostic implications

Take-Home Points

2. Acute PericarditisPR elevation in aVR may be a clue to the diagnosis

Take-Home Points

3. TCA toxicityAn R-wave >3mm in aVR is as sensitive as a QRS wider than 100ms for both seizures and arrhythmias

Take-Home Points

4. Preexcitation syndrome related narrow-complex tachycardiaST↑ in aVR provides a clue to differentiate AVNRT from AVRT

ReferencesBarrabes, 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.

Questions?