Background: Atrial fibrillation (AF) is a significant burden worldwide, and the existing treatments leave much to be desired. There are, however, opportunities to improve the safety and efficacy of the most popular treatment, radiofrequency (RF) cardiac ablation, using conductive hydrogels as an ablation mediator. Methods: Lesions were created in ex vivo ventricular tissues using bare metal traditional RF catheters and three different hydrogels with varying conductivities to assess the effect of conductivity on lesion formation. Similar procedures were performed in atrial/esophageal tissue stacks to mimic physiological AF ablation and demonstrate the initial safety profile of conductive hydrogel-mediated ablation. Results: The hydrogel mediated lesions were overall shallower and narrower than bare metal, and also exhibited less char and improved lesion homogeneity. The hydrogel also eliminated steam pops. Finally, the hydrogel appeared to be more thermally protective of the esophagus in the atrial/esophageal tissue stack, greatly reducing the lesion formation on the esophagus while still achieving transmural lesions in the atrial tissue. Conclusions: Hydrogel-mediated RF ablation holds promise as a novel method to improve ablation outcomes for AF patients. Future work will confirm this in vivo and establish the chemistry required to create a conductive hydrogel coating for RF ablation catheters.

Eliminating steam pops and improving lesion safety in atrial ablation with conductive hydrogels