title: Preferential conduction across the ventricular outflow septum in ventricular arrhythmias originating from the aortic sinus cusp.
abstract: OBJECTIVE
  The purpose of this study was to examine the relationship between the origin and breakout site of idiopathic ventricular tachycardia (VT) or premature ventricular contractions (PVCs) originating from the myocardium around the ventricular outflow tract.
  
  
  BACKGROUND
  The myocardial network around the ventricular outflow tract is not well known.
  
  
  METHODS
  We studied 70 patients with idiopathic VT (n = 23) or PVCs (n = 47) with a left bundle branch block and inferior QRS axis morphology. Electroanatomical mapping was performed in both the right ventricular outflow tract (RVOT) and aortic sinus cusp (ASC) during VT or PVCs.
  
  
  RESULTS
  The earliest ventricular activation (EVA) was recorded in the RVOT in 55 patients (group R) and in the ASC in 15 (group A). In all group R patients, the closest pace map and successful ablation were achieved at the EVA site. Although a successful ablation was achieved at the EVA site in all group A patients, the closest pace map was obtained at the EVA site in 8 and RVOT in 7 (with an excellent pace map in 4). The stimulus to QRS interval was 0 ms during pacing from the RVOT and 36 +/- 8 ms from the ASC. The distance between the EVA and perfect pace map sites in those 4 patients was 11.9 +/- 3.0 mm.
  
  
  CONCLUSIONS
  Ventricular arrhythmias originating from the ASC often show preferential conduction to the RVOT, which may render pace mapping or some algorithms using the electrocardiographic characteristics less reliable. In some of those cases, an insulated myocardial fiber across the ventricular outflow septum may exist.
authors: Division of Cardiovascular Diseases, Cardiac Rhythm Management Laboratory, University of Alabama at Birmingham, VH B147, 1670 University Boulevard, 1530 3rd Avenue South, Birmingham, Alabama 35294-0019, USA. takumi-y@fb4.so-net.ne.jp
authors: Takumi
authors: T
authors: Yamada
authors: Yoshimasa
authors: Y
authors: Murakami
authors: Naoki
authors: N
authors: Yoshida
authors: Taro
authors: T
authors: Okada
authors: Takeshi
authors: T
authors: Shimizu
authors: Junji
authors: J
authors: Toyama
authors: Yukihiko
authors: Y
authors: Yoshida
authors: Naoya
authors: N
authors: Tsuboi
authors: Masahiro
authors: M
authors: Muto
authors: Yasuya
authors: Y
authors: Inden
authors: Makoto
authors: M
authors: Hirai
authors: Toyoaki
authors: T
authors: Murohara
authors: Hugh T
authors: HT
authors: McElderry
authors: Andrew E
authors: AE
authors: Epstein
authors: Vance J
authors: VJ
authors: Plumb
authors: G Neal
authors: GN
authors: Kay
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D017115:Catheter Ablation; D022062:Electrophysiologic Techniques, Cardiac; D006329:Heart Conduction System / Q000503:physiopathology*; D006346:Heart Septum / Q000503:physiopathology*; D006801:Humans; D008875:Middle Aged; D012850:Sinus of Valsalva / Q000503:physiopathology*; D017180:Tachycardia, Ventricular / Q000503:physiopathology*; D018879:Ventricular Premature Complexes / Q000503:physiopathology*