Concurrent Application of Charge Using a Novel Circuit Prevents Heat-Related Coagulum Formation During Radiofrequency Ablation

Authors


  • This work was funded by National Institutes of Health grants R01-AG-21201-03 and Mayo Clinic Robert and Arlene Kogod Program on Aging to Dr. Jahangir, and an American Medical Association Seed Grant and a Mayo Clinic College of Medicine Grant to Dr Lim.

  • The data from this article were presented at the 2007 American College of Cardiology Young Investigator's Award Competition in New Orleans, Louisiana.

  • All intellectual property for the simultaneous charge ablation catheter system used in this study is owned by the Mayo Clinic College of Medicine and Drs. Lim, Venkatachalam, Jahangir, and Asirvatham. Ms. Johnson has a financial interest relevant to this topic.

  • Manuscript received 30 October 2007; Revised manuscript received 31 December 2007; Accepted for publication 1 January 2008.

Address for correspondence: Samuel J. Asirvatham, M.D., Department of Medicine, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55902, USA. Fax: 507-255-2550; E-mail: asirvatham.samuel@mayo.edu

Abstract

Introduction: 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.

Methods and 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.

Ancillary