title: Influence of radiofrequency energy on polypropylene sutures in atrial tissue.
abstract: OBJECTIVE
  Bipolar radiofrequency (RF) ablation is an established technique for the surgical treatment of atrial fibrillation. To create complete lesion sets, the bipolar device has to be partially inserted into the heart via a purse-string suture, which is subject to heat damage. We investigated the influence of RF ablation on the structure and function of polypropylene sutures.
  
  
  METHODS
  Six polypropylene sutures (4/0 Prolene; Ethicon, Norderstedt, Germany) were sutured ex vivo into atrial auricles from excised pig hearts. The tissue was treated by bipolar, saline-irrigated RF ablation (Cardioblate; Medtronic, Duesseldorf, Germany), until increase of tissue impedance pointed out a transmural lesion. After fixation in formaldehyde, the sutures were carefully removed and examined for ultrastructural damage using scanning electron microscopy, comparing them to sutures with intentional damage by instrumental grips. Tensile strength was tested applying a force velocity of 200 mm/min. Here, parts from the ablated zones were compared with parts from nonablated zones of the same suture.
  
  
  RESULTS
  We could not find ultrastructural damage in form of heat-induced changes in the helical polypropylene structure. Accordingly, the tensile strength of the ablated sutures (16.5 to 17.5 N) showed no difference to an untreated suture. In contrast, sutures damaged by instruments showed remarkable structural damage and could be torn without force.
  
  
  CONCLUSIONS
  Bipolar, saline-irrigated RF ablation does not damage polypropylene sutures in spite of the heat applied to the tissue. Therefore, it is safe to create bipolar epi/endocardial lesions of the heart through polypropylene purse-string sutures.
authors.affiliation: Department of Cardiovascular Surgery, University Hospital Giessen and Marburg, Rudolf-Buchheim-Strasse 7,Giessen, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Bohn
authors.forename: J
authors.initials: J
authors.lastname: Gehron
authors.forename: A
authors.initials: A
authors.lastname: Dellmann
authors.forename: A
authors.initials: A
authors.lastname: Boening
mesh_terms: D000818:Animals; D017115:Catheter Ablation; D004868:Equipment Failure; D006325:Heart Atria / Q000601:surgery; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011126:Polypropylenes / Q000737:chemistry*; D013499:Surface Properties; D013536:Suture Techniques / Q000295:instrumentation*; D013537:Sutures; D013552:Swine; D013718:Tensile Strength
chemical_list: D011126:Polypropylenes