title: The R-wave deflection interval in lead V3 combining with R-wave amplitude index in lead V1: a new surface ECG algorithm for distinguishing left from right ventricular outflow tract tachycardia origin in patients with transitional lead at V3.
abstract: BACKGROUND
  To distinguish left ventricular outflow tract (LVOT) from right ventricular outflow tract (RVOT) origin in idiopathic premature ventricular contractions or ventricular tachycardia (PVCs/VT) patients with transitional lead at V3 is still a challenge. We sought to develop a new electrocardiography (ECG) algorithm for distinguishing LVOT from RVOT origin in patients with idiopathic outflow tract PVCs/VT with precordial transitional lead at V3.
  
  
  METHODS
  We analyzed the surface ECG characteristics in a retrospective cohort of idiopathic PVCs/VT patients with transitional lead at V3 who underwent successful radiofrequency catheter ablation and developed a new surface ECG algorithm, then validated it in a prospective cohort.
  
  
  RESULTS
  A total of 82 consecutive patients (47 ± 17 years, 39% male) underwent radiofrequency catheter ablation of idiopathic outflow tract PVCs/VT between January 2006 and August 2010. Among them, 31 patients (38%) with transitional lead at V3 constituted the retrospective cohort. Based on the areas under the receiver operating characteristic curves, R-wave deflection interval in lead V3>80 ms and R-wave amplitude index in lead V1>0.30 were selected to develop the new surface ECG algorithm. It correctly identified the origin sites of eleven from 12 patients in the prospective cohort, yielding the accuracy of 91.7%.
  
  
  CONCLUSIONS
  We presented a new simple surface ECG algorithm, R-wave deflection interval in lead V3>80 ms combining with R-wave amplitude index in lead V1>0.30 which can reliably distinguish LVOT from RVOT origin in idiopathic outflow tract PVCs/VT in patients with transitional lead at V3.
authors.affiliation: Department of Cardiology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, 100730, China. Electronic address: zhongwei_cheng@hotmail.com.
authors.forename: Zhongwei
authors.initials: Z
authors.lastname: Cheng
authors.forename: Kang'an
authors.initials: K
authors.lastname: Cheng
authors.forename: Hua
authors.initials: H
authors.lastname: Deng
authors.forename: Taibo
authors.initials: T
authors.lastname: Chen
authors.forename: Peng
authors.initials: P
authors.lastname: Gao
authors.forename: Kongbo
authors.initials: K
authors.lastname: Zhu
authors.forename: Quan
authors.initials: Q
authors.lastname: Fang
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D015331:Cohort Studies; D004562:Electrocardiography / Q000295:instrumentation* / Q000592:standards; D004566:Electrodes; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012189:Retrospective Studies; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000503:physiopathology*; D016277:Ventricular Function, Left / Q000502:physiology*; D016278:Ventricular Function, Right / Q000502:physiology*; D014694:Ventricular Outflow Obstruction / Q000175:diagnosis / Q000503:physiopathology*