title: Bonus-freeze: benefit or risk? Two-year outcome and procedural comparison of a "bonus-freeze" and "no bonus-freeze" protocol using the second-generation cryoballoon for pulmonary vein isolation.
abstract: BACKGROUND
  Second-generation cryoballoon based pulmonary vein isolation has demonstrated encouraging acute and mid-term clinical outcome. Customarily, a bonus-freeze is applied after successful pulmonary vein isolation.
  
  
  OBJECTIVE
  To compare the long-term clinical outcome and safety profile of a bonus-freeze and a no bonus-freeze protocol.
  
  
  METHODS
  A total of 120 consecutive patients with paroxysmal [95/120 (79 %)] or persistent atrial fibrillation [25/120 (21 %)] underwent CB2-based PVI. Freeze-cycle duration was 240 s. In the first 60 patients a bonus-freeze was applied after successful PVI (group 1), while in the following 60 patients the bonus-freeze was omitted (group 2).
  
  
  RESULTS
  Procedure and fluoroscopy times were significantly shorter in group 2 [113.8 ± 32 vs 138.2 ± 29 min (p = 0.03) and 19.2 ± 6 vs 24.3 ± 8 min (p = 0.02)]. No differences in procedural complications were found. During a mean follow-up of 849 ± 74 (group 1) and 848 ± 101 days (group 2, p = 0.13) 69 % of patients (group 1) and 67 % of patients (group 2) remained in stable sinus rhythm without any differences between the groups (p = 0.69).
  
  
  CONCLUSIONS
  Freedom from atrial fibrillation after second-generation cryoballoon based pulmonary vein isolation and a follow-up of >2 years is comparable when applying a bonus- and a no bonus-freeze protocol, while procedure and fluoroscopy times are significantly shorter when omitting the bonus-freeze. No differences in periprocedural complications were identified.
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany.
authors.forename: Christian-H
authors.initials: CH
authors.lastname: Heeger
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany.
authors.forename: Erik
authors.initials: E
authors.lastname: Wissner
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Wohlmuth
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany.
authors.forename: Shibu
authors.initials: S
authors.lastname: Mathew
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Hayashi
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Sohns
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany.
authors.forename: Bruno
authors.initials: B
authors.lastname: Reißmann
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Lemes
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany.
authors.forename: Tilman
authors.initials: T
authors.lastname: Maurer
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany.
authors.forename: Ardan M
authors.initials: AM
authors.lastname: Saguner
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany.
authors.forename: Francesco
authors.initials: F
authors.lastname: Santoro
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Riedl
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany.
authors.forename: Feifan
authors.initials: F
authors.lastname: Ouyang
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany.
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Kuck
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany. andreasmetzner1@web.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Metzner
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D062906:Cardiac Catheters; D003452:Cryosurgery / Q000009:adverse effects / Q000295:instrumentation*; D015716:Electrocardiography, Ambulatory; D004867:Equipment Design; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D008297:Male; D008875:Middle Aged; D011667:Pulmonary Veins / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D011829:Radiation Dosage; D000069079:Radiation Exposure; D015641:Radiography, Interventional / Q000379:methods; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
keywords: Atrial fibrillation; Cryoballoon; Long-term follow-up; Pulmonary vein isolation