title: Optimal contact forces to minimize cardiac perforations before, during, and/or after radiofrequency or cryothermal ablations.
abstract: BACKGROUND
  Catheter perforations remain a major clinical concern during ablation procedures for treatment of atrial arrhythmias and may lead to life-threatening cardiac tamponade. Radiofrequency (RF) ablation alters the biomechanical properties of cardiac tissue, ultimately allowing for perforation to occur more readily. Studies on the effects of cryoablation on perforation force as well as studies defining the perforation force of human tissue are limited.
  
  
  OBJECTIVE
  The purpose of this study was to investigate the required force to elicit perforation of cardiac atrial tissue after or during ablation procedures.
  
  
  METHODS
  Effects of RF or cryothermal ablations on catheter perforation forces for both swine (n = 83 animals, 530 treatments) and human (n = 8 specimens, 136 treatments) cardiac tissue were investigated.
  
  
  RESULTS
  Overall average forces resulting in perforation of healthy unablated tissue were 406g ± 170g for swine and 591g ± 240g for humans. Post-RF ablation applications considerably reduced these forces to 246g ± 118g for swine and 362 ± 185g for humans (P <.001). Treatments with cryoablation did not significantly alter forces required to induce perforations. Decreasing catheter sizes resulted in a reduction in forces required to perforate the atrial wall (P <.001). Catheter perforations occurred over an array of contact forces with a minimum of 38g being observed.
  
  
  CONCLUSIONS
  The swine model likely underestimates the required perforation forces relative to those of human tissues. We provide novel insights related to the comparative effects of RF and cryothermal ablations on the potential for inducing undesired punctures, with RF ablation reducing perforation force significantly. These data are insightful for physicians performing ablation procedures as well as for medical device designers.
authors.affiliation: Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota; Department of Surgery, University of Minnesota, Minneapolis, Minnesota.
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Quallich
authors.affiliation: Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota.
authors.forename: Michael
authors.initials: M
authors.lastname: Van Heel
authors.affiliation: Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota; Department of Surgery, University of Minnesota, Minneapolis, Minnesota. Electronic address: iaizz001@umn.edu.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Iaizzo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D001281:Atrial Fibrillation / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects / Q000379:methods*; D003452:Cryosurgery / Q000009:adverse effects / Q000379:methods*; D004195:Disease Models, Animal; D005260:Female; D006325:Heart Atria / Q000293:injuries*; D006341:Heart Rupture / Q000209:etiology / Q000517:prevention & control*; D006801:Humans; D015994:Incidence; D007431:Intraoperative Complications / Q000453:epidemiology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D011183:Postoperative Complications / Q000453:epidemiology / Q000517:prevention & control*; D057234:Preoperative Period; D013552:Swine
keywords: Arrhythmia; Cardiac perforation; Cardiac tamponade; Catheter ablation; Cryoablation; Radiofrequency ablation