title: Quantitative assessment of a second-generation cryoballoon ablation catheter with new cooling technology-a perspective on potential implications on outcome.
abstract: OBJECTIVE
  The purpose of this study was to assess the differences in cooling behavior between the first-generation cryoballoon (CB-1G) and the second-generation cryoballoon (CB-2G) quantitatively to understand the freezing capabilities and to benefit from the improved efficacy of the CB-2G in patients with atrial fibrillation.
  
  
  METHODS
  We analyzed quantitatively the ice formation of the CB-1G and CB-2G catheters in vitro in a 37°C warm water bath during freezing for 60, 120, 180, 240, and 300s, respectively.
  
  
  RESULTS
  The mean-covered surface area and the relative coverage of the ice spots on the CB-2G were significantly different from the spots on the CB-1G for the 28-mm CBs but not for the 23-mm CBs. Whereas for the CB-1G, the ice formation was discontiguous with four isolated ice spots; the CB-2G showed a contiguous ice cap covering the entire distal part including the pole of the balloon. No homogeneous cooling behavior could be observed at the equatorial level with both catheters. Temporal differences on the ice formation could be observed for the 28-mm CB-2G but not for the 23-mm CB-2G.
  
  
  CONCLUSIONS
  The new-generation CB-2G showed more powerful and homogeneous cooling behavior, especially for the 28-mm CB. Whether this translates into higher long-term success rates is currently unknown. The impact of the more effective cooling and the longer dissolving duration of the ice cap of the new-generation CB-2G on procedural safety needs to be investigated.
authors.affiliation: Cardiology/Electrophysiology, University Hospital Basel, Petersgraben 4, 4031, Basel, Switzerland, knechts@uhbs.ch.
authors.forename: Sven
authors.initials: S
authors.lastname: Knecht
authors.forename: Michael
authors.initials: M
authors.lastname: Kühne
authors.forename: Stefan
authors.initials: S
authors.lastname: Osswald
authors.forename: Christian
authors.initials: C
authors.lastname: Sticherling
mesh_terms: D001281:Atrial Fibrillation / Q000601:surgery*; D062906:Cardiac Catheters / Q000639:trends; D017115:Catheter Ablation / Q000295:instrumentation*; D003452:Cryosurgery / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D006801:Humans; D008422:Materials Testing; D011667:Pulmonary Veins / Q000601:surgery