Catheter ablation, a minimally invasive surgical procedure that uses radiofrequency (RF), has simplified the treatment process of cardiac arrhythmias. The success of cardiac ablation procedures greatly depends on the effective lesion formation, which relies on the contact force between tissue and the tip. Thus, a real-time estimate of catheter tip contact force is essential during cardiac ablation procedures. We present the design, fabrication, and characterization of a piezoresistive Micro-Electro-Mechanical System (MEMS)-based force sensor for measuring catheter tip contact force in real-time. The sensor has four bridges with boron-doped piezoresistive elements for detecting the contact force. The sensor dimensions and the piezoresistors doping concentrations were optimized using finite element analysis. The sensor is designed to measure a catheter tip contact force between 0 – 0.8 N. An in-house indentation setup is developed and integrated with a commercial load cell to characterize the fabricated sensor. The sensor results showed a linearity of 99.5 %, maximum hysteresis of 5 %, and sensitivity of 108 ± $11 \Omega $ /N. A customized catheter tip integrated with the fabricated force sensor was tested on excised porcine heart tissues to measure the catheter tip contact force.

中文翻译：

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用于心脏消融导管的基于 MEMS 的环形压阻力传感器


导管消融是一种使用射频 (RF) 的微创外科手术，简化了心律失常的治疗过程。心脏消融手术的成功很大程度上取决于有效的病灶形成，而病灶的形成又依赖于组织与尖端之间的接触力。因此，在心脏消融过程中，实时估计导管尖端接触力至关重要。我们介绍了基于压阻微机电系统 (MEMS) 的力传感器的设计、制造和表征，用于实时测量导管尖端接触力。该传感器有四个带有硼掺杂压阻元件的电桥，用于检测接触力。使用有限元分析优化传感器尺寸和压敏电阻掺杂浓度。该传感器设计用于测量 0 – 0.8 N 之间的导管尖端接触力。开发了内部压痕装置并将其与商用称重传感器集成，以表征所制造的传感器。传感器结果显示线性度为 99.5%，最大滞后为 5%，灵敏度为 108 ± $11 \Omega $/N。在离体的猪心脏组织上测试了与制造的力传感器集成的定制导管尖端，以测量导管尖端接触力。