Black-box modeling and control of steerable ablation catheters

Minimally invasive intervention for treating cardiac arrhythmia involves ablating sources causing chaotic electrical signals in the atria. In order to perform tissue ablation, flexible catheters are steered through the vasculature from the insertion point in the groin area to the atrium. The outcome of this procedure depends on a number of factors, among which is the correct placement of the catheter tip on the target tissue. The tip/tissue contact angle is adjusted by using a manual prismatic knob on the proximal handle to bend the deflectable distal shaft of the catheter. With the goal of developing a robotics-assisted catheter manipulation system, in this paper, we focus on the problem of controlling the bending of the distal shaft when the proximal handle is used within a robotic manipulator. To this end, we apply the black-box modeling technique and perform an extensive experimental study to characterize the behavior of the catheter. The relationship between proximal measurements and the distal tip angle is then determined by fitting a model to the experimental dataset. The proposed model is used in designing a control system that adjusts the bending of the distal shaft merely based on proximal measurements with no feedback from the distal end. The performance of the designed control scheme is evaluated through experimental implementation. The results show that the control system can achieve the desired tip angle with an error less than 2 deg.