A Contact-Aided Asymmetric Steerable Catheter for Atrial Fibrillation Ablation

Electrical isolation using the ablation catheter has been widely used as the golden standard for the treatment of atrial fibrillation. Clinical practice shows that the tip orientation affects the formation of the effective lesion size. However, the traditional unidirectional or bidirectional catheter with the compliant bending shapes cannot provide great orientation capability to target the lesion paths asymmetric to the catheter's entry point. In this letter, we propose a two-dimensional (2-D) tendon-actuated asymmetric catheter to render two different bending characteristics to adapt to the special anatomy. The contact-aided compliant mechanism is adopted by designing the asymmetric blocks to form the self-collision in one lateral bending direction. Kinematics with asymmetric bends under the free bend and constraint bend are investigated. The algorithm of 3-D path exploration in the confined workspace is proposed to validate the reachability. The bending angles of two asymmetric bends are compared and the 3-D phantom study is carried out to validate its effectiveness. Results indicate that the contact-aided compliant mechanism can be integrated with the steerable catheter successfully to help form the different bending characteristics, finally improving the tip orientation capability to the specific ablation line lesions.