Optical contact force monitoring sensor for cardiac ablation catheters

Modern lifestyles can lead to various lifestyle diseases that have become the most threatening health issues to humans. In particular, heart disease is the leading global cause of death. To diagnose heart disease, cardiac catheterization is frequently conducted. The contact force between the tip of the catheter and tissue is very critical because it determines the success or failure of the procedure. In this work, an optical sensor composed of transparent, flexible, and stretchable PDMS layers forming an air cavity was developed and evaluated. The reflectance of the sensor varied with external applied force depending upon the gap between elastomeric layers placed on the catheter tip. The fabricated sensor showed very low minimum resolution (<0.1 gF), which is desired for the application. A wider dynamic range than that of the present sensor (0-0.6 gF), which is inadequate for the practical application, can be achieved by optimizing the thickness of the flexible layers.