Lead aVR--the neglected lead

The aVR is often neglected lead. It is an unipolar lead facing the right superior surface. As all the depolarisations are going away from lead aVR, all waves are negative in aVR (P, QRS, T) in normal sinus rhythm. In dextrocardia, (True and technical) the p is upright in aVR. The lead aVR is a very important lead in localisation of Coronary Artery Disease. In the presence of anterior ST elevation, ST elevation in lead aVR and V1 denotes proximal LAD obstruction where ST elevation is more in lead V1, than in aVR. In the presence of anterior ST depression, ST elevation in lead aVR indicates Left Main Coronary Artery (LMCA) Disease where ST elevation is more in aVR than in V1. In wide QRS tachycardia, tall R wave in aVR indicates Ventricular Tachycardia rather than SVT with aberrancy. In the presence of QS complexes in inferior leads, the lead aVR helps to differentiate between inferior wall MI (IWMI) and left anterior fascicular block (LAFB). Initial R in aVR is suggestive of IWMI and terminal R is suggestive of LAFB. In pericarditis, lead aVR is most often the only lead which shows reciprocal ST depression where as in Acute Infarction, usually a group of leads shows reciprocal depression. In the presence of persistent ST elevation in anterior chest leads, the R in aVR is suggestive of left ventricular aneurysm (Goldburger's sign). In acute pulmonary embolism, ST elevation in lead aVR is a bad prognostic sign. In Tricyclic antidepressant toxicity, R in aVR more than 3 mm is an adverse prognostic sign. So in variety of conditions, the aVR is proved to be a valuable lead not only in diagnosis but also in predicting the prognosis.