title: Effect of catheter tip length and position on lesion volume in temperature controlled RF ablation in canine tricuspid valve annulus.
abstract: BACKGROUND
  Radiofrequency (RF) energy has been delivered to the tricuspid valve annulus (TVA) in humans with both 4 mm and 8 mm long catheter tip electrodes to treat atrial flutter. However, lesion volume with temperature controlled RF delivery systems has not been previously characterized.
  
  
  METHODS
  In 10 anesthetized canines, a single pulse of temperature controlled RF energy at a 70 degrees C set point, 30 second duration was delivered with either a 7 Fr/4 mm tip or a 7 Fr/8 mm tip electrode in a position both anterolateral and posteroseptal to the tricuspid valve annulus (TVA). Surface echocardiogram was obtained prior and after ablation. The animals were sacrificed after ablation and the lesions underwent gross and histological examination.
  
  
  RESULTS
  Lesion size, tip temperature and power were related to tip electrode surface area (SA). Eight mm tips (SA = 59 mm2) tended to create significantly larger lesions than 4 mm tips (SA = 29 mm2). Median lesion volume was 22 vs. 1.5 mm3, respectively. Eight mm tips were also associated with higher power requirements and lower temperatures than 4 mm tips. Posteroseptal TVA lesions tended to be larger than anterolateral lesions. No significant complications were noted.
  
  
  CONCLUSIONS
  Using temperature controlled RF ablation, large lesions may be safely created on the canine TVA using 7 Fr catheters with 8 mm long tips.
authors.affiliation: Division of Cardiology, Ohio State University School of Medicine, Columbus 43210, USA. amehdirad@int-med.med.ohio-state.edu
authors.forename: A
authors.initials: A
authors.lastname: Mehdirad
authors.forename: J
authors.initials: J
authors.lastname: Gaiser
authors.forename: P
authors.initials: P
authors.lastname: Baker
authors.forename: S
authors.initials: S
authors.lastname: West
authors.forename: L
authors.initials: L
authors.lastname: Lehmkuhl
authors.forename: P
authors.initials: P
authors.lastname: Yong
authors.forename: J
authors.initials: J
authors.lastname: Meimer
authors.forename: S
authors.initials: S
authors.lastname: Nelson
mesh_terms: D000818:Animals; D001282:Atrial Flutter / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D017115:Catheter Ablation / Q000295:instrumentation*; D004285:Dogs; D004562:Electrocardiography; D006329:Heart Conduction System / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D012449:Safety; D013696:Temperature; D014261:Tricuspid Valve / Q000473:pathology / Q000601:surgery*