Volume 19, Issue 2 pp. 188-193

A Novel Hybrid Transcatheter Ablation System That Combines Radiofrequency and Cryoenergy

PAUL KHAIRY M.D., Ph.D.

PAUL KHAIRY M.D., Ph.D.

Department of Medicine and Research Center, Montreal Heart Institute, Montreal, Canada

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CATHERINE CARTIER B.Sc., M.Ing

CATHERINE CARTIER B.Sc., M.Ing

Department of Medicine and Research Center, Montreal Heart Institute, Montreal, Canada

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PATRICK CHAUVET M.Sc.

PATRICK CHAUVET M.Sc.

Department of Medicine and Research Center, Montreal Heart Institute, Montreal, Canada

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JEAN-FRANÇOIS TANGUAY M.D.

JEAN-FRANÇOIS TANGUAY M.D.

Department of Medicine and Research Center, Montreal Heart Institute, Montreal, Canada

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BERTIN SIMÉON B.Sc.

BERTIN SIMÉON B.Sc.

Department of Medicine and Research Center, Montreal Heart Institute, Montreal, Canada

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JEAN-PIERRE LALONDE Ing

JEAN-PIERRE LALONDE Ing

Department of Medicine and Research Center, Montreal Heart Institute, Montreal, Canada

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MARC DUBUC M.D.

MARC DUBUC M.D.

Department of Medicine and Research Center, Montreal Heart Institute, Montreal, Canada

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First published: 25 October 2007
Citations: 14
Address for correspondence: Dr. Paul Khairy, M.D., Ph.D., Canada Research Chair, Electrophysiology and Adult Congenital Heart Disease, Montreal Heart Institute, 5000 Bélanger Street, Montreal, Quebec, Canada, H1T 1C8. Fax: 514-376-1355; E-mail: [email protected]

The study was supported in part by a Canada Research Chair in Electrophysiology and Adult Congenital Heart Disease and by CryoCath Technologies, Inc.

Dr. Dubuc is a consultant for CryoCath Technologies Inc. Catherine Cartier, Patrick Chauvet, Bertin Siméon, and Jean-Pierre Lalonde are employees of CryoCath Technologies Inc. Mr. Chauvet holds stock options.

Manuscript received 15 July 2007; Revised manuscript received 20 August 2007; Accepted for publication 21 August 2007.

Abstract

Introduction: Radiofrequency (RF) and cryoenergy are largely considered independent modalities for the transcatheter ablation of cardiac arrhythmias. There are numerous theoretical advantages to engineering a system capable of delivering both energy forms.

Methods and Results: We designed a hybrid steerable catheter capable of delivering RF and cryoenergy independently, sequentially, and simultaneously. The novel catheter system was tested pre-clinically by creating a total of 180 ablation lesions in 20 mongrel dogs. Right atrial and right and left ventricular sites were preselected by a randomized factorial design devised to compare sequential and simultaneous RF and cryoenergy applications to standard RF, irrigated RF, and standard cryoablation. A steerable 4-mm electrode-tip hybrid catheter (“Fire and Ice”) was created by modifying a 7 F cryocatheter (Freezor™, CryoCath Technologies, Montreal, Canada). RF energy was injected via a copper wire, thermocouples were isolated to reduce RF interference, and 100 KHz band pass filters and RF chokes were added. Sequential low-dose RF (20 W, 60 seconds) preceding or following cryoablation resulted in larger lesions (P = 0.0010). The addition of RF energy did, however, produce more thrombus than cryoenergy alone, with clot detected on 82.4% versus 12.1% of ablation lesions, P < 0.0001. Simultaneously applying the two energy modalities (45 W, 10 or 30°C, 60 seconds) created more voluminous lesions than standard RF ablation (median 288.1 vs 126.1 mm3, P = 0.0333) of similar dimension to irrigated RF ablation.

Conclusion: A versatile catheter system was fashioned capable of creating standard cryoablation lesions, standard RF lesions, and simultaneous lesions of similar dimension to irrigated RF.

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