title: Radiofrequency catheter ablation of idiopathic ventricular arrhythmias originating from intramural foci in the left ventricular outflow tract: efficacy of sequential versus simultaneous unipolar catheter ablation.
abstract: BACKGROUND
  Idiopathic ventricular arrhythmias (VAs) originating from the left ventricular outflow tract (LVOT) sometimes require catheter ablation from the endocardial and epicardial sides for their elimination, suggesting the presence of intramural VA foci. This study investigated the efficacy of sequential and simultaneous unipolar radiofrequency catheter ablation from the endocardial and epicardial sides in treating intramural LVOT VAs.
  
  
  RESULTS
  Fourteen consecutive LVOT VAs, which required sequential or simultaneous irrigated unipolar radiofrequency ablation from the endocardial and epicardial sides for their elimination, were studied. The first ablation was performed at the site with the earliest local ventricular activation and best pace map on the endocardial or epicardial side. When the first ablation was unsuccessful, the second ablation was delivered on the other surface. If this sequential unipolar ablation failed, simultaneous unipolar ablation from both sides was performed. The first ablation was performed on the epicardial side in 9 VAs and endocardial side in 5 VAs. The intramural LVOT VAs were successfully eliminated by the sequential (n=9) or simultaneous (n=5) unipolar catheter ablation. Simultaneous ablation was most likely to be required for the elimination of the VAs when the distance between the endocardial and epicardial ablation sites was >8 mm and the earliest local ventricular activation time relative to the QRS onset during the VAs of <-30 ms was recorded at those ablation sites.
  
  
  CONCLUSIONS
  LVOT VAs originating from intramural foci could usually be eliminated by sequential unipolar radiofrequency ablation and sometimes required simultaneous ablation from both the endocardial and epicardial sides.
authors: From the Division of Cardiovascular Disease, University of Alabama at Birmingham (T.Y., H.T.M., H.D., V.J.P., G.N.K.); and Clinical Cardiac Electrophysiology, Department of Medicine, Georgia Regents University, Augusta (W.R.M.). takumi-y@fb4.so-net.ne.jp.
authors: Takumi
authors: T
authors: Yamada
authors: From the Division of Cardiovascular Disease, University of Alabama at Birmingham (T.Y., H.T.M., H.D., V.J.P., G.N.K.); and Clinical Cardiac Electrophysiology, Department of Medicine, Georgia Regents University, Augusta (W.R.M.).
authors: William R
authors: WR
authors: Maddox
authors: From the Division of Cardiovascular Disease, University of Alabama at Birmingham (T.Y., H.T.M., H.D., V.J.P., G.N.K.); and Clinical Cardiac Electrophysiology, Department of Medicine, Georgia Regents University, Augusta (W.R.M.).
authors: H Thomas
authors: HT
authors: McElderry
authors: From the Division of Cardiovascular Disease, University of Alabama at Birmingham (T.Y., H.T.M., H.D., V.J.P., G.N.K.); and Clinical Cardiac Electrophysiology, Department of Medicine, Georgia Regents University, Augusta (W.R.M.).
authors: Harish
authors: H
authors: Doppalapudi
authors: From the Division of Cardiovascular Disease, University of Alabama at Birmingham (T.Y., H.T.M., H.D., V.J.P., G.N.K.); and Clinical Cardiac Electrophysiology, Department of Medicine, Georgia Regents University, Augusta (W.R.M.).
authors: Vance J
authors: VJ
authors: Plumb
authors: From the Division of Cardiovascular Disease, University of Alabama at Birmingham (T.Y., H.T.M., H.D., V.J.P., G.N.K.); and Clinical Cardiac Electrophysiology, Department of Medicine, Georgia Regents University, Augusta (W.R.M.).
authors: G Neal
authors: GN
authors: Kay
mesh_terms: D000200:Action Potentials; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017115:Catheter Ablation / Q000009:adverse effects / Q000379:methods*; D004562:Electrocardiography; D004699:Endocardium / Q000503:physiopathology / Q000601:surgery*; D056149:Epicardial Mapping; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010496:Pericardium / Q000503:physiopathology / Q000601:surgery*; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D007507:Therapeutic Irrigation; D013997:Time Factors; D016896:Treatment Outcome; D018879:Ventricular Premature Complexes / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D055815:Young Adult
keywords: catheter ablation; intramural focus; left ventricular outflow tract; unipolar; ventricular tachycardia