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A Novel Dual Energy Ablation Device to Create a Box Lesion for Pulmonary Vein Isolation using Bipolar and Monopolar RF: Intra Operative Assessment using a Robotic Approach
Husam H. Balkhy1, Margot Vloka2, Peter Chapman2.
1Medical College of Wisconsin, Milwaukee, WI, USA, 2The Wisconsin Heart Hospital, Milwaukee, WI, USA.
OBJECTIVE: Recent trials show that in patients with atrial fibrillation (AF), pulmonary vein isolation (PVI) performed with bipolar surgical ablation clamps using small bilateral thoracotomies is more effective than PVI using standard catheter ablation. This improved efficacy comes with higher invasiveness; difficulty in execution and potentially more acute complications. Monopolar ‘loop’ devices overcome these drawbacks but at the potential cost of decreased efficacy. Technology that has bipolar effectiveness but with improved access and safety profiles, capable of being deployed endoscopically on a beating heart would be desirable. We evaluated an ablation system that may have all of these characteristics.
METHODS: Between April and December 2012, a Box lesion was created with robotic assistance in 17 AF patients using a right-sided unilateral approach with a new suction-applied bipolar ‘loop’ device. The device pulls atrial wall into its cavity and out of the circulating blood to create a bipolar lesion. Bipolar ablation was applied for 60 seconds at 70°C followed by monopolar ablation for 60 seconds at 70°C. Conduction block testing was performed as well as rapid atrial pacing (RAP) on the PV to induce sustained AF post-ablation. The LAA was occluded via three left-sided 5 mm ports using multiple snares under TEE guidance. The tip of the appendage was incised emptying it of blood.
RESULTS: Four of 17 patients had persistent AF. Eight patients had a staged hybrid ablation. Three patients had concomitant TECAB (totally endoscopic) LIMA-LAD. Average robot time for the AF procedure was 109+14 min. Exit and entrance conduction block was achieved in all patients at a minimum of 5 times threshold. RAP of the PVs was unable to produce sustained AF in 15 of 17 patients. There were no peri-operative deaths or morbidity.
CONCLUSIONS: Our initial experience and intra-operative assessment shows that this bipolar epicardial ‘loop’ ablation technology is well designed for easy use in an endoscopic environment and is safe and effective in producing electrical PVI. Clinical and longer-term follow up is warranted. 
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