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.