Efficacy of a novel bipolar radiofrequency ablation device on the beating heart for atrial fibrillation ablation: A long-term porcine study
Received 12 May 2009; received in revised form 16 May 2009; accepted 8 June 2009. published online 01 February 2010.
Objective
Over recent years, a variety of energy sources have been used to replace the traditional incisions of the Cox maze procedure for the surgical treatment of atrial fibrillation. This study evaluated the safety and efficacy of a new bipolar radiofrequency ablation device for atrial ablation in a long-term porcine model.
Methods
Six pigs underwent a Cox maze IV procedure on a beating heart off cardiopulmonary bypass using the AtriCure Isolator II bipolar ablation device (AtriCure, Inc, Cincinnati, Ohio). In addition, 6 pigs underwent median sternotomy and pericardiotomy alone to serve as a control group. All animals were allowed to survive for 30 days. Each pig underwent induction of atrial fibrillation and was then humanely killed to remove the heart en bloc for histologic assessment. Magnetic resonance imaging scans were also obtained preoperatively and postoperatively to assess atrial and ventricular function, pulmonary vein anatomy, valve function, and coronary artery patency.
Results
All animals survived the operation. Electrical isolation of the left atrial appendage and the pulmonary veins was documented by pacing acutely and at 30 days in all animals. No animal that underwent the Cox maze IV procedure was able to be induced into atrial fibrillation at 30 days postoperatively, compared with all the sham animals. All 257 ablations examined were discrete, linear, and transmural, with a mean lesion width of 2.2 ± 1.1 mm and a mean lesion depth of 5.3 ± 3.0 mm.
Conclusions
The AtriCure Isolator II device was able to create reliable long-term transmural lesions of the modified Cox maze procedure on a beating heart without cardiopulmonary bypass 100% of the time. There were no discernible effects on ventricular or valvular function.
Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St Louis, Mo
Address for reprints: Ralph J. Damiano, Jr, MD, Washington University School of Medicine, Barnes-Jewish Hospital, Suite 3108 Queeny Tower, 1 Barnes-Jewish Hospital Plaza, St Louis, MO 63110.
Disclosures: The study was supported by AtriCure; Ralph Damiano reports advisory and lecture fees from AtriCure; Richard Schuessler reports advisory and lecture fees and grant support from AtriCure.
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