title: Twelve-lead ECG features to identify ventricular tachycardia arising from the epicardial right ventricle.
abstract: BACKGROUND
  Usefulness of 12-lead ECG for predicting an epicardial origin for ventricular tachycardia (VT) arising from the right ventricle (RV) has not been assessed. An epicardial approach is sometimes warranted to eliminate RV VT.
  
  
  OBJECTIVE
  The purpose of this study was investigate the hypothesis that specific ECG features identify an epicardial origin for RV VT.
  
  
  METHODS
  To mimic an endocardial or epicardial origin, we paced representative sites in 13 patients undergoing RV endocardial/epicardial mapping (134/180 pace map sites).
  
  
  RESULTS
  QRS duration from epicardial vs endocardial sites was not different (183 +/- 27 ms vs 185 +/- 28 ms, P = .3). Reported cut-off values for identifying epicardial left ventricular origin, pseudo-delta wave (> or =34 ms), intrinsicoid deflection time (> or =85 ms), and RS complex (> or =121 ms) did not apply to the RV. A Q wave in lead II, III, or aVF was more likely noted from inferior epicardial vs endocardial sites (53/73 vs 16/43, P <.01). A Q wave in lead I was more frequently present from epicardial vs endocardial anterior RV sites (30/82 vs 5/52, P <.001). QS in lead V(2) was noted from anatomically matched epicardial anterior RV sites (22/33 vs 13/33, P <.05). In the RV outflow tract, no ECG feature distinguishing epicardial/endocardial origin reached statistical significance.
  
  
  CONCLUSIONS
  A Q wave or QS in leads that best reflect local activation suggest an epicardial origin for RV depolarization and may help in identifying a probable epicardial site of origin for RV VT. QRS duration and reported criteria for epicardial origin of VT in the left ventricle do not identify a probable epicardial origin in the RV.
authors.affiliation: Cardiovascular Division, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Victor
authors.initials: V
authors.lastname: Bazan
authors.forename: Rupa
authors.initials: R
authors.lastname: Bala
authors.forename: Fermin C
authors.initials: FC
authors.lastname: Garcia
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Sussman
authors.forename: Edward P
authors.initials: EP
authors.lastname: Gerstenfeld
authors.forename: Sanjay
authors.initials: S
authors.lastname: Dixit
authors.forename: David J
authors.initials: DJ
authors.lastname: Callans
authors.forename: Erica
authors.initials: E
authors.lastname: Zado
authors.forename: Francis E
authors.initials: FE
authors.lastname: Marchlinski
mesh_terms: D017115:Catheter Ablation; D003937:Diagnosis, Differential; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010496:Pericardium / Q000503:physiopathology*; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery