title: Initial experience using a forward directed, high-intensity focused ultrasound balloon catheter for pulmonary vein antrum isolation in patients with atrial fibrillation.
abstract: BACKGROUND
  A high-intensity-focused ultrasound balloon catheter (HIFU-BC) is designed to isolate pulmonary veins (PV) outside the ostia (PV antrum). This catheter uses a parabolic CO2 balloon (behind water balloon) to focus a 20-, 25-, or 30-mm diameter ring of ultrasound forward of the balloon (parallel to catheter shaft). The purpose of this study is to test the safety and efficacy of the HIFU-BC for PV antrum isolation in patients with atrial fibrillation (AF).
  
  
  RESULTS
  Twenty-seven patients with paroxysmal (19 patients) or persistent (8 patients) AF were studied. Double transseptal puncture was performed for left atrial deployment of a Lasso catheter (for PV mapping) and the 14 Fr HIFU-BC. The HIFU-BC was positioned outside the PV orifice over a guidewire. HIFU energy (acoustic power 45 watts) was applied for 40 seconds with a 20-mm sonicating ring and 40 or 60 seconds with a 25-mm or 30-mm sonicating ring. No other ablation system was utilized. PV antrum isolation was attempted using HIFU-BC in 78 of 104 PVs (25/27 RSPVs, all 23 LSPVs, all 23 LIPVs, all four left common trunks and 3/27 RIPVs). HIFU-BC successfully isolated 68 (87%) of the 78PV antra with 1-26 (median 3) HIFU applications. The complications include transient bleeding from a distal branch of the left superior PV resulting from guidewire manipulation in one patient and right phrenic nerve injury in another patient. No PV stenosis (>50% narrowing) and no LA-esophageal fistula occurred. At the 12-month follow-up, 16 (59%) of the 27 patients were free of symptomatic episodes of AF (only 3 of the 16 patients were receiving antiarrhythmic medications).
  
  
  CONCLUSIONS
  Forward-focused HIFU applications isolated PVs outside the PV ostium with elimination of AF in 16 (59%) of the 27 patients at 12 months following the single ablation procedure.
authors.affiliation: Cardiac Arrhythmia Research Institute and Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA. hiroshi-nakagawa@ouhsc.edu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakagawa
authors.forename: Matthias
authors.initials: M
authors.lastname: Antz
authors.forename: Tom
authors.initials: T
authors.lastname: Wong
authors.forename: Boris
authors.initials: B
authors.lastname: Schmidt
authors.forename: Sabine
authors.initials: S
authors.lastname: Ernst
authors.forename: Feifan
authors.initials: F
authors.lastname: Ouyang
authors.forename: Thomas
authors.initials: T
authors.lastname: Vogtmann
authors.forename: Richard
authors.initials: R
authors.lastname: Wu
authors.forename: Katsuaki
authors.initials: K
authors.lastname: Yokoyama
authors.forename: Deborah
authors.initials: D
authors.lastname: Lockwood
authors.forename: Sunny S
authors.initials: SS
authors.lastname: Po
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Beckman
authors.forename: D Wyn
authors.initials: DW
authors.lastname: Davies
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Kuck
authors.forename: Warren M
authors.initials: WM
authors.lastname: Jackman
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000628:therapy*; D006328:Cardiac Catheterization / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods*; D002404:Catheterization / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods*; D003251:Constriction, Pathologic / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D006470:Hemorrhage / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010791:Phrenic Nerve / Q000293:injuries; D011667:Pulmonary Veins / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D013923:Thromboembolism / Q000209:etiology; D016896:Treatment Outcome; D014463:Ultrasonography