title: Two-year outcome after pulmonary vein isolation using the second-generation 28-mm cryoballoon: lessons from the bonus freeze protocol.
abstract: BACKGROUND
  Pulmonary vein isolation (PVI) using the second-generation cryoballoon (CB2) in patients with paroxysmal and persistent atrial fibrillation (AF) has demonstrated encouraging acute and mid-term results. Follow-up data on outcome beyond 1-year is lacking. The purpose of this analysis was to investigate the 2-year clinical outcome after CB2-based PVI.
  
  
  METHODS
  Sixty patients (age 62 ± 11 years) with paroxysmal [45/60 (75%) patients] or short-standing persistent AF [15/60 (25%) patients] underwent 28-mm CB2-based PVI. Freeze-cycle duration was 240 s. After successful PVI, a bonus freeze-cycle of the same duration was applied. Follow-up was based on outpatient clinic visits at 3, 6, 12, 18, and 24 months including 24 h Holter-ECGs and telephone interviews. Recurrence was defined as any symptomatic and/or documented atrial tachyarrhythmia (ATA) episode >30 s following a 3-month blanking period.
  
  
  RESULTS
  A total of 231 pulmonary veins (PV) were identified and 230/231 (99.6%) PVs were successfully isolated. Phrenic nerve palsy occurred in 2/60 (3.3%) patients. No other periprocedural complications occurred. Follow-up was available for 59/60 (98%) patients with a mean duration of 838 ± 67 days. A total of 43/59 (73%) patients remained in stable sinus rhythm. In 10/16 (63%) patients with ATA recurrence, a repeat procedure was performed using radiofrequency energy. The overall success rate after a maximum of two ablation procedures and a follow-up period of 838 ± 67 days was 88% (52/59) patients.
  
  
  CONCLUSIONS
  Patients with paroxysmal or short-persistent AF undergoing PVI using the 28-mm CB2 demonstrated a 73% 2-year single-procedure clinical success rate.
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
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany.
authors.forename: Christian-Hendrik
authors.initials: CH
authors.lastname: Heeger
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: Bruno
authors.initials: B
authors.lastname: Reißmann
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Rillig
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany.
authors.forename: Roland Richard
authors.initials: RR
authors.lastname: Tilz
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: Christine
authors.initials: C
authors.lastname: Lemes
authors.affiliation: Department of Cardiology, Asklepios Klinik St. Georg, Lohmühlenstr. 5, 20099, Hamburg, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Deiß
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
authors.initials: A
authors.lastname: Saguner
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.
authors.forename: Erik
authors.initials: E
authors.lastname: Wißner
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D003452:Cryosurgery / Q000379:methods*; D015716:Electrocardiography, Ambulatory; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010243:Paralysis / Q000453:epidemiology / Q000209:etiology; D010791:Phrenic Nerve / Q000293:injuries; D011667:Pulmonary Veins / Q000601:surgery*; D012008:Recurrence; D013997:Time Factors; D016896:Treatment Outcome
keywords: Atrial fibrillation; Cryoballoon; Long-term follow-up; Pulmonary vein isolation