title: Electrocardiographic difference between ventricular arrhythmias from the right ventricular outflow tract and idiopathic right ventricular arrhythmias.
abstract: BACKGROUND
  Ventricular arrhythmias (VA) arising from arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) and idiopathic right ventricular outflow tract ventricular arrhythmias (RVOT-VA) share the pattern of left bundle branch block (LBBB)/inferior axis. The existence of QRS notching showed a discriminating effect of the two conditions in recent research; however, there are little data regarding the difference in the distribution of QRS notching. The aim of this study was to compare the VA morphology between the two conditions, especially evaluating the diagnostic role of QRS notching.
  
  
  METHODS
  Electrocardiographic (ECG) recordings of VA episode with LBBB/inferior axis of 16 ARVD/C and 45 idiopathic RVOT-VA patients (30 originated from the septum, 15 from the free-wall) were gathered and compared.
  
  
  RESULTS
  ARVD/C had longer mean QRS duration in all 12 leads, and significant differences existed in leads Ⅰ,Ⅱ,Ⅲ, aVL, aVF, and V1 (P < 0.05). Lead Ⅰ had the largest mean difference of 25.1 ± 5.8 ms. In addition, ARVD/C had more R-wave transition in lead V5 or later (37.5% vs 8.9%, P < 0.01).The presence of QRS notching (15/16 [93.8%] vs 36/45 [80.0%], P = 0.20) and the total number of leads expressing notching (2.88 ± 2.0 vs 2.80 ± 2.0, P = 0.90) were not different between ARVD/C and idiopathic RVOT-VA. However, QRS notching existing simultaneously in leads I and aVL was more common in ARVD/C (43.8% vs13.3%, P = 0.011).
  
  
  CONCLUSIONS
  Longer QRS duration, later precordial R/S transition, and QRS notching in lateral leads (leads Ⅰ and aVL) are useful in discriminating ARVD/C from idiopathic RVOT-VA.
authors: Cardiac Arrhythmia Center, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China.
authors: Lan
authors: L
authors: Ren
authors: Zheng
authors: Z
authors: Liu
authors: Yuhe
authors: Y
authors: Jia
authors: Pihua
authors: P
authors: Fang
authors: Jielin
authors: J
authors: Pu
authors: Shu
authors: S
authors: Zhang
mesh_terms: D000328:Adult; D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*; D019571:Arrhythmogenic Right Ventricular Dysplasia; D002037:Bundle-Branch Block / Q000150:complications; D003937:Diagnosis, Differential; D004562:Electrocardiography; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D012189:Retrospective Studies
keywords: diagnosis; electrocardiogram; ventricular arrhythmia