Preferential Conduction Across the Ventricular Outflow Septum in Ventricular Arrhythmias Originating From the Aortic Sinus Cusp

Takumi Yamada, Yoshimasa Murakami, Naoki Yoshida, Taro Okada, Takeshi Shimizu, Junji Toyama, Yukihiko Yoshida, Naoya Tsuboi, Masahiro Muto, Yasuya Inden, Makoto Hirai, Toyoaki Murohara, Hugh T. McElderry, Andrew E. Epstein, Vance J. Plumb, G. Neal Kay

Research output: Contribution to journalArticlepeer-review

128 Scopus citations


Objectives: The purpose of this study was to examine the relationship between the origin and breakout site of idiopathic ventricular tachycardia (VT) or premature ventricular contractions (PVCs) originating from the myocardium around the ventricular outflow tract. Background: The myocardial network around the ventricular outflow tract is not well known. Methods: We studied 70 patients with idiopathic VT (n = 23) or PVCs (n = 47) with a left bundle branch block and inferior QRS axis morphology. Electroanatomical mapping was performed in both the right ventricular outflow tract (RVOT) and aortic sinus cusp (ASC) during VT or PVCs. Results: The earliest ventricular activation (EVA) was recorded in the RVOT in 55 patients (group R) and in the ASC in 15 (group A). In all group R patients, the closest pace map and successful ablation were achieved at the EVA site. Although a successful ablation was achieved at the EVA site in all group A patients, the closest pace map was obtained at the EVA site in 8 and RVOT in 7 (with an excellent pace map in 4). The stimulus to QRS interval was 0 ms during pacing from the RVOT and 36 ± 8 ms from the ASC. The distance between the EVA and perfect pace map sites in those 4 patients was 11.9 ± 3.0 mm. Conclusions: Ventricular arrhythmias originating from the ASC often show preferential conduction to the RVOT, which may render pace mapping or some algorithms using the electrocardiographic characteristics less reliable. In some of those cases, an insulated myocardial fiber across the ventricular outflow septum may exist.

Original languageEnglish (US)
Pages (from-to)884-891
Number of pages8
JournalJournal of the American College of Cardiology
Issue number9
StatePublished - Aug 28 2007
Externally publishedYes


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