Dexterous Intramyocardial Needle Ablation (d-INA): Design, Fabrication, and In-Vivo Validation
Chang Zhou, Charles P. Hong, Yifan Wang, Ehud J. Schmidt, Junichi Tokuda, Aravindan Kolandaivelu, Yue Chen
TL;DR
This work tackles the challenge of VT ablation requiring deep intramyocardial lesions by introducing the dexterous intramyocardial needle ablation (d-INA) system, a three-part toolset with a steerable outer sheath, a steerable inner catheter, and an integrated ablation needle designed to navigate the LV's complex geometry. The authors demonstrate high distal dexterity and stiffness modulation, achieving deep, transmural lesions in ex-vivo tissue and in vivo swine, with lesion depths of $11.6 \pm 3$ mm and transmurality of $92\% \pm 11\%$, significantly exceeding conventional endocardial RF ablation by about $219\%$ depth. Bench-top tests quantify bending curvatures $(0.088 \mathrm{mm}^{-1}, 0.114 \mathrm{mm}^{-1})$ and validate planar and non-planar configurations, while ex-vivo experiments show tunable needle penetration through tissue, aided by irrigation. The findings suggest d-INA as a promising platform for deep, targeted VT ablation, with future work focusing on physics-based workspace modeling and MRI-guided closed-loop control to translate this into a clinical workflow.
Abstract
Radiofrequency ablation is widely used to prevent ventricular tachycardia (VT) by creating lesions to inhibit arrhythmias; however, the current surface ablation catheters are limited in creating lesions that are deeper within the left ventricle (LV) wall. Intramyocardial needle ablation (INA) addresses this limitation by penetrating the myocardium and delivering energy from within. Yet, existing INA catheters lack adequate dexterity to navigate the highly asymmetric, trabeculated LV chamber and steer around papillary structures, limiting precise targeting. This work presents a novel dexterous INA (d-INA) toolset designed to enable effective manipulation and creation of deep ablation lesions. The system consists of an outer sheath and an inner catheter, both bidirectionally steerable, along with an integrated ablation needle assembly. Benchtop tests demonstrated that the sheath and catheter reached maximum bending curvatures of 0.088~mm$^{-1}$ and 0.114~mm$^{-1}$, respectively, and achieved stable C-, S-, and non-planar S-shaped configurations. Ex-vivo studies validated the system's stiffness modulation and lesion-creation capabilities. In-vivo experiments in two swine demonstrated the device's ability to reach previously challenging regions such as the LV summit, and achieved a 219\% increase in ablation depth compared with a standard ablation catheter. These results establish the proposed d-INA as a promising platform for achieving deep ablation with enhanced dexterity, advancing VT treatment.