title: Determinants of successful ablation of idiopathic ventricular tachycardias with left bundle branch block morphology from the right ventricular outflow tract.
abstract: The aim of the study was to define the factors that may predict the outcomes of radiofrequency ablation from the right ventricular outflow tract (RVOT) in patients with idiopathic VT with a QRS morphology of LBBB. Endocardial mapping and RF ablation from the RVOT were performed in 35 patients (14 men, mean age 41 +/- 14 years), and VT was successfully ablated in 30 patients. There was no significant difference with regard to clinical characteristics and electrophysiological findings between patients with successful and failed ablation. The VTs with successful ablation showed an rS (n = 16) or QS (n = 14) pattern in lead V1, and all five VTs with failed ablation showed an rS pattern in lead V1. Although the absence of an R wave in lead V1 did not differ between patients with successful and failed ablation (P = 0.13), the absence of an R wave in lead V1 predicted VT successfully ablated from the RVOT (positive predictive value 100%; negative predictive value 24%). The VTs with successful ablation had a median precordial transitional zone at lead V4 (range V3-V6), whereas all five VTs with failed ablation had precordial transition zones at lead V3 (P = 0.004). Furthermore, a presence of an R wave in lead V1 associated with a precordial transition zone at lead V3 predicted VT not successfully ablated from the RVOT (positive predictive value 100%; negative predictive value 100%). In conclusion, some VTs with LBBB and inferior or normal axis cannot be ablated from the RVOT. The presence of an R wave in lead V1 associated with a precordial transition zone at lead V3 suggest that some VTs may not arise from the RVOT.
authors.affiliation: Department of Medicine, National Yang-Ming University, School of Medicine, Veterans General Hospital, Taipei, Taiwan. ufae0061@ms7.hinet.net
authors.forename: Shih-Huang
authors.initials: SH
authors.lastname: Lee
authors.forename: Ching-Tai
authors.initials: CT
authors.lastname: Tai
authors.forename: Chern-En
authors.initials: CE
authors.lastname: Chiang
authors.forename: Jin-Long
authors.initials: JL
authors.lastname: Huang
authors.forename: Chuen-Wang
authors.initials: CW
authors.lastname: Chiou
authors.forename: Yu-An
authors.initials: YA
authors.lastname: Ding
authors.forename: Mau-Song
authors.initials: MS
authors.lastname: Chang
authors.forename: Shih-Ann
authors.initials: SA
authors.lastname: Chen
mesh_terms: D000328:Adult; D002037:Bundle-Branch Block / Q000503:physiopathology*; D017115:Catheter Ablation; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D017180:Tachycardia, Ventricular / Q000503:physiopathology / Q000601:surgery*