title: Electrocardiographic characteristics of repetitive monomorphic right ventricular tachycardia originating near the His-bundle.
abstract: BACKGROUND
  Most idiopathic nonreentrant ventricular tachycardia (VT) and ventricular premature contractions (VPCs) arise from the right or left ventricular outflow tract (OT). However, some right ventricular (RV) VT/VPCs originate near the His-bundle region. The aim of this study was to investigate ECG characteristics of VT/VPCs originating near the His-bundle in comparison with right ventricular outflow tract (RVOT)-VT/VPCs.
  
  
  RESULTS
  Ninety RV-VT/VPC patients underwent catheter mapping and radiofrequency ablation. ECG variables were compared between VT/VPCs originating from the RVOT and near the His-bundle. Ten patients had foci near the His-bundle (HIS group), with the His-bundle local ventricular electrogram preceding the QRS onset by 15-35 msec (mean: 22 msec) and His-bundle pacing produced a nearly identical ECG to clinical VT/VPCs. The HIS group R wave amplitude in the inferior leads (lead III: 1.0 +/- 0.6 mV) was significantly lower than that of the RVOT group (1.7 +/- 0.4 mV, P < 0.05). An R wave in aVL was present in 6 of 10 HIS group patients, while almost all RVOT group patients had a QS pattern in aVL. Lead I in HIS group exhibited significantly taller R wave amplitudes than RVOT group. HIS group QRS duration in the inferior leads was shorter than that of the RVOT group. Eight of 10 HIS group patients exhibited a QS pattern in lead V1 compared to 14 of 81 RVOT group patients. HIS group had larger R wave amplitudes in leads V5 and V6 than RVOT group.
  
  
  CONCLUSIONS
  VT/VPCs originating near the His-bundle have distinctive ECG characteristics. Knowledge of the characteristic QRS morphology may facilitate catheter mapping and successful ablation.
authors.affiliation: Division of Cardiology, Musashino Red Cross Hospital, Tokyo, Japan. yamauchi@musashino.jrc.or.jp
authors.forename: Yasuteru
authors.initials: Y
authors.lastname: Yamauchi
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Aonuma
authors.forename: Atsushi
authors.initials: A
authors.lastname: Takahashi
authors.forename: Yukio
authors.initials: Y
authors.lastname: Sekiguchi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Hachiya
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Yokoyama
authors.forename: Koji
authors.initials: K
authors.lastname: Kumagai
authors.forename: Akihiko
authors.initials: A
authors.lastname: Nogami
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Iesaka
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Isobe
mesh_terms: D000328:Adult; D000368:Aged; D002036:Bundle of His / Q000503:physiopathology* / Q000601:surgery; D002037:Bundle-Branch Block / Q000503:physiopathology; D017115:Catheter Ablation; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D017180:Tachycardia, Ventricular / Q000503:physiopathology* / Q000601:surgery; D016896:Treatment Outcome; D014694:Ventricular Outflow Obstruction / Q000503:physiopathology* / Q000601:surgery