Abstract：Among electrocardiographic leads, lead aVR usually receives less attention in clinical evaluation of electrocardiogram (ECG).However recent researches reveal important roles lead aVR plays in various ways.The classical clinical applications of lead aVR include the identifications of sinus rhythm and axis and the diagnosis of dextrocardia, exchanges of the upper limb leads and ventricular hypertrophy. There were several other clinical applications discovered recently. Firstly, when acute coronary syndrome attacks, ST segment elevation in lead aVR could indicates the stenosis of left main coronary artery, proximal left anterior descending or three-vesseled coronary artery disease. When ST-segment-elevation typed myocardial infarction occurs, elevation or depression of ST segment could serve as independent predictor of mortality of inpatients and be utilized in the risk stratification. Secondly, lead aVR could be applied in differentiating wide or narrow QRS tachyarrhythmias. Combined with lead V1 and V2, lead aVR of surface ECG can be utilized in the estimation of the cycle length of right atrial fibrillation. It implies that the amplitude of P wave in lead aVR was a powerful predictor of postoperative atrial fibrillation. And the morphology of R wave in lead aVR could be helpful in riskstratifying patients with Brugada syndrome. Thirdly, when right ventricle is overloaded, ST segment elevation in lead aVR can provide some valuable information for predicting the death rate(by univariate regression analysis) and complication of acute pulmonary embolism. The R wave delay in lead aVR is proved to be an independent predictor of overloaded right ventricle and more prevalent in patients with pulmonary stenosis.Among patients with idiopathic pulmonary arterial hypertension, R wave in lead aVR >4 mm in combination with R in V1 >6 mm, R/S in V1 >1, R/S in V5 to R/S in V1 <0.04 and P in Ⅱ>2.5 mm could confirm the diagnosis of right ventricular hypertrophy. Fourthly, when Wolff-Parkinson-White syndrome probably occurs, a three stepwise criteria which is composed of the presence of both PR interval≤120 ms and PR dispersion≥20 ms, the absence of initial forward wave(septal R wave) in lead aVR and horizontal QRS transition in lead V1 or before could be utilized in identifying ventricular preexcitation and the criteria proves to be very sensitive and specific. Furthermore, a serial monitoring of R wave and R/S ratio in lead aVR might be informative in predicting the recovery of consciousness from toxicity due to tricyclic antidepressants overdose. In addition, when acute pericarditis attacks, ST segment depression and PR segment elevation in lead aVR become characteristic representations of the disease, that is, knuckle sign, which may help in the diagnosis of acute pericarditis for it’s possibly the earliest and the only change of ECG.
[1] Ozmen N，Yiginer O，Uz O，et al. ST elevation in the lead aVR during exercise treadmill testing may indicate left main coronary artery disease[J].Kardiol Pol，2010，68(10)：1107-1111.[2] Kosuge M，Ebina T，Hibi K，et al. Early, accurate, noninvasive predictors of left main or 3vessel disease in patients with nonSTsegment elevation acute coronary syndrome[J]. Circ J， 2009,73(6):1105-1110.[3] Kukla P，Bryniarski L，Dudek D，et al. Prognostic significance of ST segment changes in lead aVR in patients with acute inferior myocardial infarction with ST segment elevation[J]. Kardiol Pol，2012，70(2)：111-118.[4] Wong CK，Gao W，Stewart RA，et al. aVR ST elevation: an important but neglected sign in ST elevation acute myocardial infarction[J]. Eur Heart J，2010，31（15）: 1845-1853.[5] Wong CK，Gao W，Stewart RA，et al.The prognostic meaning of the full spectrum of aVR STsegment changes in acute myocardial infarction[J]. Eur Heart J，2012，33（3）:384-392.[6] Ho YL，Lin LY，Lin JL，et al. Usefulness of STsegment elevation in lead aVR during tachycardia for determining the mechanism of narrow QRS complex tachycardia[J].Am J Cardiol，2003，92（12）:1424-1428.[7] Haghjoo M，Bahramali E，Sharifkazemi M，et al. Value of the aVR lead in differential diagnosis of atrioventricular nodal reentrant tachycardia[J]. Europace，2012，14(11): 1624-1628.[8] Vereckei A，Duray G，Szénási G，et al. New algorithm using only lead aVR for differential diagnosis of wide QRS complex tachycardia[J].Heart Rhythm，2008，5（1）:89-98.[9] Jastrzebski M，Kukla P，Czarnecka D，et al. Comparison of five electrocardiographic methods for differentiation of wide QRScomplex tachycardias[J]. Europace，2012，14（8）:1165-1171.[10] Lazar S，Dixit S，Marchlinski FE，et al. Presence of lefttoright atrial frequency gradient in paroxysmal but not persistent atrial fibrillation in humans[J]. Circulation，2004，110（20）：3181-3186.[11] Lazar S，Dixit S，Callans DJ，et al. Effect of pulmonary vein isolation on the lefttoright atrial dominant frequency gradient in human atrial fibrillation[J]. Heart Rhythm，2006，3（8）:889-895.[12] Hassaguerre M，Sanders P，Hocini M，et al. Changes in atrial fibrillation cycle length and inducibility during catheter ablation and their relation to outcome[J]. Circulation，2004，109（24）：3007-3013.[13] Ravi KC，Krummen DE，Tran AJ，et al. Electrocardiographic measurements of regional atrial fibrillation cycle length[J].Pacing Clin Electrophysiol，2009，32(Suppl 1): S66-S71.[14] Rader F，Costantini O，Jarrett C，et al. Quantitative electrocardiography for predicting postoperative atrial fibrillation after cardiac surgery[J]. J Electrocardiol，2011，44(6):761-767.[15] Babai Bigi MA，Aslani A，Shahrzad S. aVR sign as a risk factor for lifethreatening arrhythmic events in patients with Brugada syndrome[J]. Heart Rhythm，2007，4（8）:1009-1012.[16] Kukla P，Dlugopolski R，Krupa E，et al. Electrocardiography and prognosis of patients with acute pulmonary embolism[J]. Cardiol J，2011，18(6):648-653.[17] Can MM，ozveren O，Biteker M，et al. Role of electrocardiographic changes in discriminating acute or chronic right ventricular pressure overload[J]. Anadolu Kardiyol Derg，2013，13（4）：344-349.[18] Kope′c G，Tyrka A，MiszalskiJamka T，et al. Electrocardiogram for the diagnosis of right ventricular hypertrophy and dilation in idiopathic pulmonary arterial hypertension[J]. Circ J，2012，76（7）:1744-1749.[19] Eisenberger M，Davidson NC，Todd DM，et al. A new approach to confirming or excluding ventricular preexcitation on a 12lead ECG[J]. Europace，2010，12（1）:119-123.[20] Thanacoody HK，Thomas SH. Tricyclic antidepressant poisoning: cardiovascular toxicity[J]. Toxicol Rev，2005，24（3）:205-214.[21] Choi KH，Lee KU.Serial monitoring of lead aVR in patients with prolonged unconsciousness following tricyclic antidepressant overdose[J]. Psychiatry Investig，2008，5（4）:247-250.[22] SanaeiZadeh H.Comment on “Serial monitoring of lead aVR in patients with prolonged unconsciousness following tricyclic antidepressant overdose” [J]. Psychiatry Investig，2012，9（1）：85-86.[23] Spodick DH. Acute pericarditis：current concepts and practice[J].JAMA，2003，289（9）：1150-1153.
2013, Vol. 22 
