title: Failure to reach the optimal temperature during cryoablation due to refrigerant cylinder problem.
abstract: BACKGROUND
  Pulmonary vein (PV) isolation is considered as a key to atrial fibrillation (AF) treatment. Cryoballoon ablation is an effective therapy for PV isolation for AF with minimal side effects and was approved by the US Food and Drug Administration (FDA) several years ago. Successful isolation of PVs during cryoablation depends on the balloon temperature and helps in early identification of noneffective cryoballoon applications. A lower balloon temperature has been associated with long-term success in isolation of PVs.
  
  
  METHODS
  At the start of the procedure, the cryoconsole displayed "low refrigerant level". After a few cycles of successful cryoballoon applications, for a fresh application for a new PV, the optimal temperature was not obtained in spite of obtaining good grade of occlusion and ostial positioning for right inferior pulmonary vein (RIPV). Later, immediately after changing the refrigerant cylinder, suitable temperature was obtained. We faced this situation thrice in a span of eight months.
  
  
  CONCLUSIONS
  Low refrigerant level may cause nonoptimal temperature during cryoablation, which can be resolved by premature change of a gas cylinder.
authors.affiliation: Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands.
authors.forename: Narendra
authors.initials: N
authors.lastname: Kumar
authors.affiliation: Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands.
authors.forename: Trang
authors.initials: T
authors.lastname: Dinh
authors.affiliation: Department of Cardiology, Al Qassimi Hospital, Sharjah, U.A.E.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Magdi Abbas
authors.affiliation: Macquarie University and Westmead Hospital, University of Sydney, Sydney, Australia.
authors.forename: Kevin
authors.initials: K
authors.lastname: Phan
authors.affiliation: Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands.
authors.forename: Randolph
authors.initials: R
authors.lastname: Manusama
authors.affiliation: Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Philippens
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Centre and Cardiovascular Research Institute Maastricht (CARIM), Maastricht, The Netherlands.
authors.forename: Jos
authors.initials: J
authors.lastname: Maessen
authors.affiliation: Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands.
authors.forename: Carl
authors.initials: C
authors.lastname: Timmermans
keywords: Atrial Fibrillation; Cryoablation; Pulmonary vein; refrigeration