title: Relevance of endocavitary structures in ablation procedures for ventricular tachycardia.
abstract: BACKGROUND
  Radiofrequency (RF) ablation for ventricular tachycardia (VT) has high failure rates. Whether endocavitary structures (ECS) such as the papillary muscles (PMs), moderator bands (MBs), or false tendons (FTs) impact VT ablation is unknown.
  
  
  RESULTS
  We retrospectively reviewed records of 190 consecutive patients presenting for VT ablation and identified 46 (24%) where ECS affected ablation. In 31 of 46 patients (67%), the ECS created difficulty with catheter manipulation (n = 20), interpretation of pace map data (n = 7), or with accurately defining a scar (n = 4). In 15 of 46 (33%), specific mapping and RF energy delivery targeting the ECS itself was necessary to eliminate the arrhythmia. Detailed electroanatomic mapping was performed in 11 of 15 (73%), noncontact mapping in 3 of 15 (20%), multielectrode catheter mapping in 1 of 15 (7%), and intracardiac ultrasound in 14 of 15 (93%) patients. The ablated ECS was a PM in 5 of 15, the MB in 7 of 15, and an FT in 3 of 15. The arrhythmogenic substrate on the ECS was a focus of automatic tachycardia in 9 of 15 and the slow zone responsible for reentrant arrhythmia in the remaining 6 of 15. Successful elimination of tachycardia without recurrence was obtained in all 15 cases. There was no evidence of valvular damage or disruption of the valvular apparatus.
  
  
  CONCLUSIONS
  During VT ablation procedures, ECS should be considered for specific mapping and targeted ablation. Once recognized, these structures can be successfully targeted for ablation without valve damage.
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Department of Pediatrics and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA.
authors.forename: Omar
authors.initials: O
authors.lastname: Abouezzeddine
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Suleiman
authors.forename: Traci
authors.initials: T
authors.lastname: Buescher
authors.forename: Suraj
authors.initials: S
authors.lastname: Kapa
authors.forename: Paul A
authors.initials: PA
authors.lastname: Friedman
authors.forename: Arshad
authors.initials: A
authors.lastname: Jahangir
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Mears
authors.forename: Dorothy J
authors.initials: DJ
authors.lastname: Ladewig
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Munger
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Hammill
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Packer
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Asirvatham
mesh_terms: D000328:Adult; D018780:Body Surface Potential Mapping / Q000379:methods*; D017115:Catheter Ablation / Q000009:adverse effects / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D011379:Prognosis; D012189:Retrospective Studies; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000601:surgery*; D016896:Treatment Outcome