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Evaluation of Integrated Bipolar and Unipolar Epicardial Ablation
Andy C. Kiser, Hayden Pappas, Kelly Garner, Anil Gehi, John Paul Mounsey.
University of North Carolina, Chapel Hill, NC, USA.
Background: Bipolar lesion creation is accepted as the most effective method to create transmural atrial ablations. However, the creation of a comprehensive ablation pattern on the left and right atrium with current bipolar devices is difficult on the beating heart. We evaluate a novel integrated ablation device, that creates both bipolar and unipolar lesions in a linear pattern on the beating porcine heart and report initial clinical results.
Methods: Using six porcine models, we evaluated effectiveness of creating beating heart ablation lesions by transmurality and conduction block. Isolating lesions were created on the left and right atria of the beating porcine heart. After bipolar and unipolar lesions were sequentially created, conduction block was confirmed and the lesion depth examined histologically. Additionally, eleven patients with paroxysmal (n=4) or persistent (n=7) atrial fibrillation who failed medical management had subcutaneous monitor implantation and underwent epicardial ablation to isolate the left atrium and right atrial surface with simultaneous endocardial mapping and catheter ablation.
Results: Linear lesions were created successfully on the surface of the beating porcine heart (see graph). Conduction block at 20mV was confirmed at all isolated areas and 96.4% of the lesion sections were full-thickness and transmural at histology. Clinically, the electroanatomic maps of the left atrium confirmed elimination of electrogram voltage amplitude. All patients left the hospital in sinus rhythm without periprocedural stroke, death or major complication.
Conclusions: The new device enables both unipolar and bipolar lesion creation in a linear, low-profile manner, thus enabling effective creation of a comprehensive lesion pattern on the epicardial surface of the beating heart. Initial clinical evaluation demonstrates successful elimination of electrical activity within the epicardial ablation pattern that is augmented by endocardial therapy. Long-term outcomes evaluation is underway. 
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