title: Catheter ablation of ventricular arrhythmias originating in the vicinity of the His bundle: significance of mapping the aortic sinus cusp.
abstract: BACKGROUND
  There is a close anatomical relationship between the right coronary cusp (RCC) and noncoronary aortic cusp (NCC) and sites recording His bundle (HB) activation in the right ventricle (RV).
  
  
  OBJECTIVE
  The purpose of this study was to examine the electrocardiographic and electrophysiological characteristics of ventricular arrhythmias (VAs) that originate near the HB and their potential as predictors of successful catheter ablation sites.
  
  
  METHODS
  We studied 147 consecutive patients undergoing successful catheter ablation of idiopathic VAs originating from the ventricular outflow tract of either ventricle or the HB region.
  
  
  RESULTS
  In 13 (9%) patients with an origin in the RCC (n = 5), NCC (n = 1), or RV HB region (n = 7), the local RV activation in the HB region preceded the QRS onset. In two VAs originating from the RCC or NCC, failed radiofrequency applications near the HB region in the RV delayed the near-field ventricular electrogram and separated the far-field electrograms before the QRS onset in the HB region. The QRS transition in the precordial leads did not discriminate between an RV origin near the HB and an NCC or RCC origin. A QS pattern in lead aVL might be helpful for predicting an RCC origin.
  
  
  CONCLUSIONS
  VAs originating near the HB have similar electrocardiographic and electrophysiological characteristics, regardless of whether the ablation site is in the RV or aortic sinuses because of the close anatomical relationship of these structures and rapid transseptal conduction. When RV mapping reveals an earliest ventricular activation in the HB region during VAs, mapping in the RCC and NCC should be added to accurately identify the site of origin.
authors.affiliation: Division of Cardiovascular Diseases, Cardiac Rhythm Management Laboratory, University of Alabama at Birmingham, Birmingham, Alabama 35294-0019, USA. takumi-y@fb4.so-net.ne.jp
authors.forename: Takumi
authors.initials: T
authors.lastname: Yamada
authors.forename: Hugh T
authors.initials: HT
authors.lastname: McElderry
authors.forename: Harish
authors.initials: H
authors.lastname: Doppalapudi
authors.forename: G Neal
authors.initials: GN
authors.lastname: Kay
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D002036:Bundle of His / Q000503:physiopathology*; D017115:Catheter Ablation; D004562:Electrocardiography; D004594:Electrophysiology; D005260:Female; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D012850:Sinus of Valsalva / Q000503:physiopathology*; D017180:Tachycardia, Ventricular / Q000503:physiopathology*