title: Ablation of idiopathic ventricular tachycardia in two separate regions of the outflow tract: prevalence and electrocardiographic characteristics.
abstract: Few studies have clarified the prevalence and characteristics of idiopathic outflow tachycardia (OT-VT) with an altered QRS morphology after radiofrequency catheter ablation (RFCA), requiring additional RFCA applications at a different portion of the outflow tract (OT) to abolish the OT-VT. Among 344 patients (97 VTs and 247 premature ventricular contractions), 12 (3.5%; VTs-7, PVCs-5; 6 women) had dynamic QRS morphology changes following the RFCA, requiring additional RFCA applications at a different portion to abolish the OT-VT. In 8 of 12 patients (67%), this phenomenon occurred following RFCA at right (RVOT; n = 7) or left ventricular (LVOT; n = 1) endocardial sites of the OT: The second OT-VT was consistently associated with an increase in the R-wave amplitude in the inferior leads, and in five it was finally abolished by RFCA at the left sinus of Valsalva (LSV). Conversely, in four patients (33%), the second OT-VT appeared after RFCA at the LSV: two required additional RFCA applications at the LVOT to abolish the second OT-VT, and one at the RVOT, and all were associated with a decrease in the R-wave amplitude in the inferior leads. This kind of dynamic QRS morphology change was often observed when RFCA was applied to either the first or second OT-VT at a right or left ventricular endocardial site, with the other site being the LSV. A detailed continuous observation of the QRS morphology, especially of the R-wave in the inferior leads, is important for identifying changes in the QRS morphology during RFCA.
authors.affiliation: Division of Cardiology, Gunma Prefectural Cardiovascular Center, Maebashi, Gunma, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kaseno
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tada
authors.forename: Sachiko
authors.initials: S
authors.lastname: Ito
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Tadokoro
authors.forename: Tohru
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Kohei
authors.initials: K
authors.lastname: Miyaji
authors.forename: Shigeto
authors.initials: S
authors.lastname: Naito
authors.forename: Shigeru
authors.initials: S
authors.lastname: Oshima
authors.forename: Akihiko
authors.initials: A
authors.lastname: Nogami
authors.forename: Koichi
authors.initials: K
authors.lastname: Taniguchi
mesh_terms: D000328:Adult; D000368:Aged; D017115:Catheter Ablation; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery*; D018487:Ventricular Dysfunction, Left; D018497:Ventricular Dysfunction, Right