Force Torque Jig for Catheter Calibration
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Solution Overview
Problem
During cardiac ablation procedures using basket-type catheters, the applied torque can lead to sudden untwisting of the distal end assembly, potentially causing trauma to heart tissue and interfering with the ablation process.
Innovation Solution
A calibration system that includes a jig capable of measuring the positions of 3D sensors on the catheter distal end assembly, applying forces and torques, and warning the operator if the torque exceeds a preset limit to prevent sudden untwisting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the distal end assembly is made flexible to enable minimally invasive insertion and positioning, then ease of operation and adaptability are improved, but the assembly becomes susceptible to sudden untwisting under torque which can cause tissue trauma
Solution Approach 1:
The calibration jig applies predetermined torques to the distal end assembly before actual use, establishing a torque-orientation correspondence that predicts when sudden untwisting may occur. This preliminary characterization allows operators to avoid dangerous torque levels during procedures.
Solution Approach 2:
The system measures the orientation of 3D sensors on the assembly under applied torque and feeds back this information to create a correspondence model. During procedures, this model provides feedback to warn operators when torque approaches levels that could cause sudden untwisting.
2Productivity
If multiple electrodes are activated simultaneously to reduce procedure time, then productivity is improved, but the risk of sudden untwisting and tissue trauma increases due to higher cumulative torque
Solution Approach 1:
The torque-orientation correspondence provides real-time feedback during simultaneous multi-electrode activation, warning operators when cumulative torque from multiple electrodes approaches dangerous levels that could cause sudden untwisting and tissue trauma.
Solution Approach 2:
The system allows operators to apply torque close to but not exceeding the calibrated safe limits for simultaneous electrode activation. By operating at partial capacity rather than maximum, the system enables efficient multi-electrode use while preventing harmful sudden untwisting.
3Adaptability or versatility
If the catheter shaft is made long to reach distant heart sites, then adaptability is improved, but the torque transmitted to the distal end assembly increases, raising the risk of sudden untwisting
Solution Approach 1:
The calibration jig characterizes the torque-orientation relationship for the specific catheter length and flexibility before use. This preliminary data allows prediction of safe operating torque levels that account for the extended shaft length and reduced torsional stiffness.
Solution Approach 2:
The system adjusts the safe torque thresholds based on the calibrated parameters specific to each catheter's length and flexibility characteristics. Longer catheters with greater flexibility have lower torque thresholds to prevent sudden untwisting.
Data Source
AI summary
Apparatus for calibrating a catheter, consisting of a jig having a base defining a first axis orthogonal to the base. A frame is coupled to the base, and is configured to rotate about a second axis orthogonal to the first axis. A catheter support is coupled to the frame and is configured to retain the catheter and to rotate the catheter about a third axis orthogonal to the second axis. The jig also has a gauge that is coupled to the base and to a distal end assembly of the t catheter. The gauge is configured to provide an indication of a force on the distal end assembly in response to translation of the distal end assembly along the first axis.