Materials &
Methods
Measurement
setup
We constructed and validated a bench setup that can assess the accuracy
of the force sensors integrated in force sensing ablation catheters. The
measurement system consists of an acrylic glass tank containing 0.9%
saline solution heated to 37°C to emulate the electrical and thermal
properties of the human body (Figure 1). It further offers a catheter
fixation mechanism and a suspended platform on which a force can be
applied. The force is redirected to the outside of the water bath onto a
precision scale (resolution = 0.5g, FXN 3K-4N, Kern, Balingen, Germany),
using low friction pulleys. The force pulls on a counterweight lying on
the scale, consequently lifting the weight (Figure 1). After initial
zeroing, the force applied to the platform can be read off directly from
the scale. The surface of the platform consists of a slightly
compressible polymeric foam, mimicking the flexibility of myocardial
tissue. A custom-made catheter fixation mechanism allows holding the
catheter at different angles from 0° to 90° against the platform. 0° is
defined as perpendicular to the platform, such that the force is applied
axially to the catheter (Z-axis), while 90° is defined as parallel to
the platform, resulting in a force applied radially to the tip of the
catheter (X- and Y-axis). The position of the catheter can be adjusted
vertically to adjust the force exerted onto the platform. For simplicity
reason, the terms “weight” and “force” are used interchangeably.