title: Concurrent application of charge using a novel circuit prevents heat-related coagulum formation during radiofrequency ablation.
abstract: BACKGROUND
  Thromboembolism resulting from coagulum formation on the catheter and electrode surfaces is a serious complication with radiofrequency ablation procedures for heart rhythm disorders. Why coagulum occurs despite therapeutic heparinization is unclear. In this report, we demonstrate a novel approach to minimize coagulum formation based on the electromolecular characteristics of fibrinogen.
  
  
  RESULTS
  Atomic force microscopy was used to establish that fibrinogen deposited on surfaces underwent conformational changes that resulted in spontaneous clot formation. We then immersed ablation catheters that were uncharged, negatively, or positively charged in heparinized blood for 30 minutes and noted the extent of clot formation. In separate experiments, ablation catheters were sutured to the ventricle of an excised porcine heart immersed in whole, heparinized blood and radiofrequency ablation performed for 5 minutes with and without charge delivered to the catheter tips. Electron microscopy of the catheter tips showed surface coverage of fibrin clot of the catheter to be 33.8% for negatively charged catheters, compared with 84.7% (P = 0.01) in noncharged catheters. There was no significant difference in surface coverage of fibrin clot between positively charged catheters (93.8%) and noncharged catheters (84.7%, P = ns). In contrast, the thickness of surface clot coverage for positively charged catheters was 87.5%, compared with 28.45% (P= 0.03) for noncharged catheters and 11.25% (P = 0.03) for negatively charged catheters, compared with noncharged catheters.
  
  
  CONCLUSIONS
  We describe a novel method of placing negative charge on electrodes during ablation that reduced coagulum formation. This may decrease thromboembolism-related complications with radiofrequency ablation procedures.
authors: Division of Cardiology, Department of Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota 55902, USA.
authors: Bernard
authors: B
authors: Lim
authors: Kalpathi L
authors: KL
authors: Venkatachalam
authors: Arshad
authors: A
authors: Jahangir
authors: Susan B
authors: SB
authors: Johnson
authors: Samuel J
authors: SJ
authors: Asirvatham
mesh_terms: D001777:Blood Coagulation / Q000528:radiation effects*; D017115:Catheter Ablation / Q000295:instrumentation* / Q000379:methods*; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005337:Fibrin / Q000737:chemistry* / Q000528:radiation effects; D005340:Fibrinogen / Q000737:chemistry* / Q000528:radiation effects; D006358:Hot Temperature; D055672:Static Electricity
chemical_list: D005337:Fibrin; D005340:Fibrinogen