Stablepoint (Boston Scientific, Marlborough, MA, USA):
The tip is suspended by a machined precision spring, which can be compressed and bent. Three inductive sensors, comprising a ferromagnetic core and a coil are located in the proximal part of the catheter tip. The ferromagnetic cores are attached to the tip and move within the coils as the tip is deflected by an applied force. This results in a change of inductance of individual sensors. Knowing the rigidity of the spring, the axial and lateral forces acting on the tip can be calculated by Hooke’s law.