Design and Analysis of MEMS-Based Sensors Toward Measuring Catheter Contact Forces

Abstract

A contact force sensor is a critical clinical unit while performing cardiac ablation procedures. The success rate of these procedures is determined by the effective contact between the tip and the heart tissues. Using a miniaturized, susceptible tri-axial force sensor in the cardiac ablation catheter is quintessential to determine the force acting on the tip accurately. This paper discusses the design, fabrication, and comparison of two MEMS-based force sensors that can potentially be integrated with the catheter tip for better sensitivity. The working principle, shape (ring-type), and outer dimensions of both the sensors are similar, with a strategically positioned narrow rectangular cavity in the second sensor. Finite element analysis is performed to validate the performances of both sensors with the experimental results. The experiments show that sensor 2 (with the rectangular cavity on bridges) has <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 1.84\times $ </tex-math></inline-formula> higher sensitivity than sensor 1 (bridges with no rectangular cavity). The results demonstrate the possibility of integrating the sensor with the catheter tip for measuring catheter contact force.