title: Impact of freezing time and balloon size on the thermodynamics and isolation efficacy during pulmonary vein isolation using the second generation cryoballoon.
abstract: BACKGROUND
  The differences in ablation characteristics of freezing time and balloon size using second generation cryoballoon are still unknown.
  
  
  RESULTS
  Twenty-six dogs underwent pulmonary vein (PV) isolation. Balloon and tissue temperatures (left atrial-PV junction, phrenic nerve, and internal esophagus) were monitored. The ablation duration was randomized to either 3 or 4 minutes, which did not show significant differences in temperature profiles, PV isolation success rate, complications, or histological changes. Twenty dogs underwent cryoablation using 28-mm cryoballoon, 6 dogs were done using the 23-mm cryoballoon. Positioning of the 23-mm cryoballoon was more distal in the PV, which resulted in better PV occlusion. Temperature profiles showed lower temperatures in the 23-mm cryoballoon than in the 28-mm cryoballoon (inner balloon, median [range]: -51.5 [-66.0 to -31.0] versus -43.0 [-64.0 to -26.0]°C, P<0.001; balloon surface: -43.0 [-60.0 to -15.8] versus -6.5 [-46.2 to 28.9]°C, P<0.001; left atrial-PV junction: -6.7 [-20.0 to 21.4] versus 15.8 [-14.4 to 35.1]°C, P<0.001), and trended toward a higher PV isolation success rate in the 23-mm cryoballoon. Histologically, deeper extensions of ablative lesions into the PV were seen with 23-mm cryoballoon, and larger ablative lesions were seen in the left atrial antrum using 28-mm cryoballoon.
  
  
  CONCLUSIONS
  The efficacy of 3-minute ablation was not significantly different from 4-minute ablation in dogs. The 23-mm cryoballoon had a greater cooling effect than the 28-mm cryoballoon for small PVs, but showed narrower ablative lesions in the left atrial antrum.
authors.affiliation: From the Translational Interventional Electrophysiology Laboratory, Mayo Clinic, Rochester, MN.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Takami
authors.affiliation: From the Translational Interventional Electrophysiology Laboratory, Mayo Clinic, Rochester, MN.
authors.forename: H Immo
authors.initials: HI
authors.lastname: Lehmann
authors.affiliation: From the Translational Interventional Electrophysiology Laboratory, Mayo Clinic, Rochester, MN.
authors.forename: Juna
authors.initials: J
authors.lastname: Misiri
authors.affiliation: From the Translational Interventional Electrophysiology Laboratory, Mayo Clinic, Rochester, MN.
authors.forename: Kay D
authors.initials: KD
authors.lastname: Parker
authors.affiliation: From the Translational Interventional Electrophysiology Laboratory, Mayo Clinic, Rochester, MN.
authors.forename: Ray I
authors.initials: RI
authors.lastname: Sarmiento
authors.affiliation: From the Translational Interventional Electrophysiology Laboratory, Mayo Clinic, Rochester, MN.
authors.forename: Susan B
authors.initials: SB
authors.lastname: Johnson
authors.affiliation: From the Translational Interventional Electrophysiology Laboratory, Mayo Clinic, Rochester, MN. packer@mayo.edu.
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Packer
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000503:physiopathology / Q000601:surgery*; D001831:Body Temperature / Q000502:physiology*; D057785:Catheters; D003452:Cryosurgery / Q000295:instrumentation*; D004285:Dogs; D004867:Equipment Design; D005615:Freezing; D006325:Heart Atria / Q000503:physiopathology / Q000601:surgery*; D006329:Heart Conduction System / Q000503:physiopathology / Q000601:surgery*; D011667:Pulmonary Veins / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome
keywords: atrial fibrillation; cryoballoon; esophagus; freezing; pulmonary vein; thermodynamics