Prominent R wave in lead V1: Electrocardiographic differential diagnosis

Tall lead VI (tall RV1), defined as an R/S ratio equal to or greater than 1 , is not an infrequent occurrence in emergency department patients. This el ectrocardiographic finding exists as a normal variant in only 1% of patient s. Physicians should therefore be familiar with the differential diagnosis for this important QRS configuration. The electrocardiographic entities whi ch can present with this finding include right bundle branch block, left ve ntricular ectopy, right ventricular hypertrophy, acute right ventricular di lation (acute right heart strain), type a Wolff-Parkinson-White syndrome, p osterior myocardial infarction, hypertrophic cardiomyopathy, progressive mu scular dystrophy, dextrocardia, misplaced precordial leads, and normal vari ant. Various cases are presented to highlight the different causes of the t all RV1. Copyright (C) 2001 by W.B. Saunders Company.