title: Initial human feasibility of infusion needle catheter ablation for refractory ventricular tachycardia.
abstract: BACKGROUND
  Ablation of ventricular tachycardia (VT) is sometimes unsuccessful when ablation lesions are of insufficient depth to reach arrhythmogenic substrate. We report the initial experience with the use of a catheter with an extendable/retractable irrigated needle at the tip capable of intramyocardial mapping and ablation.
  
  
  RESULTS
  Sequential consenting patients with recurrent VT underwent ablation with the use of a needle-tipped catheter. At target sites, the needle was advanced 7 to 9 mm into the myocardium, permitting pacing and recording. Infusion of saline/iodinated contrast mixture excluded perforation and ensured intramyocardial deployment. Further infusion was delivered before and during temperature-controlled radiofrequency energy delivery through the needle. All 8 patients included (6 male; mean age, 54) with a mean left ventricular ejection fraction of 29% were refractory to multiple antiarrhythmic drugs, and 1 to 4 previous catheter ablation attempts (epicardial in 4) had failed. Patients had 1 to 7 (median, 2) VTs present or inducible; 2 were incessant. Some intramyocardial VT mapping was possible in 7 patients. A mean of 22 (limits, 3-48) needle ablation lesions were applied in 8 patients. All patients had at least 1 VT terminated or rendered noninducible. During a median of 12 months follow-up, 4 patients were free of recurrent VT, and 3 patients were improved, but had new VTs occur at some point during follow-up. Two died of the progression of preexisting heart failure without recurrent VT. Complications included tamponade in 1 patient and heart block in 2 patients.
  
  
  CONCLUSIONS
  Intramyocardial infusion-needle catheter ablation is feasible and permits control of some VTs that have been refractory to conventional catheter ablation therapy, warranting further study.
authors.affiliation: Department of Medicine, QEII Health Sciences Centre, Halifax, NS, Canada (J.L.S., R.P., C.J.G.); Biosense Webster, Diamond Bar, CA (C.B., R.B.); Department of Medicine, University of Leiden Medical Center, Leiden, the Netherlands (K.Z.); Cardiac Sciences Department, Libin Cardiovascular Institute, Calgary, AB, Canada (V.K.); and Department of Medicine, Brigham and Women's Hospital, Boston, MA (W.G.S.).
authors.forename: John L
authors.initials: JL
authors.lastname: Sapp
authors.forename: Christopher
authors.initials: C
authors.lastname: Beeckler
authors.forename: Robert
authors.initials: R
authors.lastname: Pike
authors.forename: Ratika
authors.initials: R
authors.lastname: Parkash
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Gray
authors.forename: Katja
authors.initials: K
authors.lastname: Zeppenfeld
authors.forename: Vikas
authors.initials: V
authors.lastname: Kuriachan
authors.forename: William G
authors.initials: WG
authors.lastname: Stevenson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D017115:Catheter Ablation / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods*; D004351:Drug Resistance; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009339:Needles; D012008:Recurrence; D017180:Tachycardia, Ventricular / Q000188:drug therapy / Q000601:surgery*; D016896:Treatment Outcome
chemical_list: D000889:Anti-Arrhythmia Agents
keywords: catheter ablation; tachycardia, ventricular