title: Electrophysiological and anatomical background of the fusion configuration of diastolic and presystolic Purkinje potentials in patients with verapamil-sensitive idiopathic left ventricular tachycardia.
abstract: BACKGROUND
  It is unclear whether false tendons (FTs) are a substantial part of the reentry circuit of verapamil-sensitive idiopathic left ventricular tachycardia (ILVT). This study aimed to prove the association between FTs and the slow conduction zone by evaluating the electro-anatomical relationship between the so-called diastolic Purkinje (Pd) potentials and FTs using an electro-anatomical mapping (EAM) system (CARTO).
  
  
  METHODS
  The 1st protocol evaluated the spatial distribution of Pd and presystolic Purkinje (Pp) potentials in 6 IVLT patients using a conventional CARTO system. In the remaining 2 patients (2nd protocol), the electro-anatomical relationship between the Pd-Pp fusion potential and the septal connection of the FT was evaluated using an EAM system incorporating an intra-cardiac echo (CARTO-Sound).
  
  
  RESULTS
  Pd potentials were observed in the posterior-posteroseptal region of the LV and had a slow conduction property, whereas Pp potentials were widely distributed in the interventricular (IV) septum. At the intersection of the 2 regions, which was located in the mid-posteroseptal area, both Pd and Pp potentials were closely spaced and often had a fused configuration. In the latter 2 patients (2nd protocol), it was confirmed that the intra-cardiac points at which the Pd-Pp fusion potential was recorded were located in the vicinity of the attachment site of the FT to the IV septum. In all patients, ILVTs were successfully eliminated by the application of radiofrequency at those points.
  
  
  CONCLUSIONS
  FTs may at least partly contribute to the formation of the Pd potential, and thus form a critical part of the reentry circuit of ILVT.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Nippon Medical School, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Taniguchi
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Tokai University Hachioji Hospital, 1838 Ishikawa-machi Hachioji-shi, Tokyo 192-0032, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Nippon Medical School, Chiba-Hokuso Hospital, Chiba, Japan.
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Maruyama
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Tokai University Hachioji Hospital, 1838 Ishikawa-machi Hachioji-shi, Tokyo 192-0032, Japan.
authors.forename: Norishige
authors.initials: N
authors.lastname: Morita
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Nippon Medical School, Tokyo, Japan.
authors.forename: Meiso
authors.initials: M
authors.lastname: Hayashi
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Nippon Medical School, Tokyo, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Miyauchi
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Nippon Medical School, Tokyo, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Shimizu
keywords: False tendon; Idiopathic left ventricular tachycardia; Purkinje potential; Reentry circuit; Verapamil-sensitive