title: Lesion Size and Safety Comparison Between the Novel Flex Tip on the FlexAbility Ablation Catheter and the Solid Tips on the ThermoCool and ThermoCool SF Ablation Catheters.
abstract: BACKGROUND
  Next-generation catheters have been developed to reduce irrigation volume and preserve power delivery. A novel design uses a flexible tip (FlexAbility™ catheter) that directs flow to the contact surface. Because of recent safety issues with new catheters, we undertook a study in a canine heart with 3 irrigated catheters to compare efficacy and safety.
  
  
  METHODS
  Endocardial ablation was performed by 2 independent operators in 12 anesthetized canines with the FlexAbility (St. Jude Medical), ThermoCool™ (Biosense Webster), and ThermoCool™ SF (Biosense Webster) catheters. Endocardial RF lesions were delivered with each catheter in all 4 chambers of each animal for 52 ± 16 seconds. Each chamber was randomized to receive ablation from one catheter with recording of safety events. Cardiac pathology was performed with triphenyl tetrazolium chloride stain.
  
  
  RESULTS
  Average lesion dimensions were not significantly different between the 3 catheters. FlexAbility™ demonstrated a lower risk of steam pops relative to ThermoCool SF (P-value = 0.013) despite equal mean power and radiofrequency time. High-temperature generator shutdowns were observed with FlexAbility™ but not with either ThermoCool catheter. High-temperature shutdowns were associated with larger average impedance drops (28.5 ohms vs. 19 ohms) without compromising lesion size.
  
  
  CONCLUSIONS
  The FlexAbility™ tip is safe and effective with no significant difference in lesion sizes compared to both standard ThermoCool and ThermoCool SF. FlexAbility™ has a significantly lower risk of steam pops compared to ThermoCool SF in a beating heart as defined predominantly by an abrupt rise of impedance.
authors.affiliation: Loyola University Medical Center, Maywood, Illinois.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Winterfield
authors.affiliation: St. Jude Medical, St. Paul, Minnesota.
authors.forename: James
authors.initials: J
authors.lastname: Jensen
authors.affiliation: St. Jude Medical, St. Paul, Minnesota.
authors.forename: Therese
authors.initials: T
authors.lastname: Gilbert
authors.affiliation: University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Francis
authors.initials: F
authors.lastname: Marchlinski
authors.affiliation: Texas Cardiac Arrhythmia Institute, Austin, Texas.
authors.forename: Andrea
authors.initials: A
authors.lastname: Natale
authors.affiliation: Mayo Clinic, Rochester, Minnesota.
authors.forename: Douglas
authors.initials: D
authors.lastname: Packer
authors.affiliation: Mount Sinai Medical Center, New York, New York, USA.
authors.forename: Vivek
authors.initials: V
authors.lastname: Reddy
authors.affiliation: St. Jude Medical, St. Paul, Minnesota.
authors.forename: Srijoy
authors.initials: S
authors.lastname: Mahapatra
authors.affiliation: Loyola University Medical Center, Maywood, Illinois.
authors.forename: David J
authors.initials: DJ
authors.lastname: Wilber
mesh_terms: D000818:Animals; D006328:Cardiac Catheterization / Q000009:adverse effects / Q000295:instrumentation*; D062906:Cardiac Catheters; D017115:Catheter Ablation / Q000009:adverse effects / Q000295:instrumentation*; D004285:Dogs; D017097:Electric Impedance; D004699:Endocardium / Q000473:pathology / Q000601:surgery*; D004867:Equipment Design; D006358:Hot Temperature; D008422:Materials Testing; D023421:Models, Animal; D007507:Therapeutic Irrigation / Q000009:adverse effects / Q000295:instrumentation*
keywords: catheter ablation; flexibility catheter; lesion; radiofrequency; steam pop