Design of a Conductive Hydrogel Coating to Improve Catheter-Tissue Coupling in Radiofrequency Ablation

Radiofrequency ablation is a mainstay of cardiac rhythm management despite high recurrence rates. Current radiofrequency ablation catheters are limited by poor contact with trabeculated cardiac tissue that promotes uneven heating with hot spots that cause collateral damage and regions of incomplete ablation that promote recurrence. Herein, we report on a conductive hydrogel coating of radiofrequency ablation catheters to improve tissue contact while promoting efficient energy transfer. A method was developed to graft a polyether urethane diacrylamide hydrogel to the distal tip of the catheter that maintained stable adhesion following drying, sterilization, and rehydration. The coating also remained intact after passage through an introducer sheath and 50 cycles of radiofrequency ablation at clinical power. The hydrogel-coated catheter demonstrated enhanced tissue contact that was dependent on hydrogel modulus. Hydrogel-mediated ablation prevented steam pop incidence and generated homogeneous lesions in an ex vivo ablation model; however, increased hydrogel conductivity is needed to achieve comparable lesion dimensions as the bare metal catheter and prevent coating damage at higher power. Collectively, these results establish a tunable hydrogel coating method that addresses limitations of conventional radiofrequency ablation and offers a promising approach to enhance the safety and efficacy of cardiac ablation therapies.