Catheter Contact Force Sensor Using Inductive Coils
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Solution Overview
Problem
Existing technologies for diagnosing and treating cardiac arrhythmias, such as atrial fibrillation, lack effective methods for verifying electrode contact with cardiac tissue during ablation procedures.
Innovation Solution
A spring assembly integrated with an intravascular catheter, featuring a compressible framework and inductive coils, which provides electrical signals indicative of force applied to the catheter tip, enabling precise contact verification and force measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional pressure transducers or impedance measurement methods are used to verify electrode contact, then the device complexity is reduced, but the measurement precision and reliability of contact verification are insufficient
Solution Approach 1:
The patent replaces traditional mechanical pressure transducers with an electromagnetic sensing system using inductive coils. The contact force sensor uses inductive coupling between a drive coil and sense coil to detect catheter tip position and contact force, substituting mechanical measurement with electromagnetic field-based measurement to achieve higher precision while maintaining acceptable device complexity
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the catheter and tissue. The inductive coils generate and detect changes in the magnetic field caused by tissue contact, using the magnetic field as a mediator to transfer information about contact force without requiring direct mechanical contact sensors at the catheter tip
2Measurement precision
If fluoroscopic imaging is used to verify electrode contact, then measurement precision is improved, but the use of energy and time consumption increase significantly
Solution Approach 1:
The patent substitutes fluoroscopic imaging (which requires high-energy X-rays) with a low-energy electromagnetic inductive sensing system. The inductive coils detect contact force through changes in electrical impedance caused by magnetic field variations, consuming minimal energy compared to fluoroscopic imaging while providing comparable or superior measurement precision
Solution Approach 2:
The sensing system uses the catheter's own electrical circuitry and magnetic field generation capabilities to perform self-diagnosis of contact status. The inductive coils continuously monitor their own impedance changes, enabling the system to self-verify electrode contact without requiring external imaging equipment or additional energy-intensive diagnostic tools
3Reliability
If spring assembly with inductive coils is integrated into the catheter, then the measurement precision and reliability of force detection are improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges the spring assembly structure with the inductive coil sensing system into an integrated force measurement unit. The spring mechanism provides mechanical compliance while the inductive coils embedded in or attached to the spring structure detect position and force, combining mechanical and electromagnetic functions into a single integrated component that improves reliability without requiring separate assembly of multiple independent systems
Solution Approach 2:
The spring assembly with inductive coils serves multiple functions simultaneously: it provides mechanical support and compliance, acts as a position sensor through inductive coupling, and functions as a force sensor by detecting impedance changes. This multi-functionality reduces the need for separate components and simplifies the overall manufacturing process despite the advanced sensing capabilities
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The spring assembly allows for accurate determination of three-dimensional force vectors applied to the catheter tip, enhancing the precision and safety of ablation procedures by ensuring proper tissue contact and minimizing tissue damage.
Implementation Method 1
The spring assembly can include a first inductive coil and a second inductive coil. The inductive coils are used to detect force applied to the catheter tip through changes in magnetic field coupling
Implementation Method 2
a compressible framework extending between the first and second mounting surfaces. The compressible framework is compressible parallel to the longitudinal axis to move the inductive coils in the pair toward each other
Data Source
AI summary
A spring assembly usable with an intravascular catheter can include a tubular body, two mounting surfaces, and a compressible framework. The tubular body extends along a longitudinal axis and is sized to traverse vasculature. Each mounting surface can be configured to engage a substantially planar electrical circuit and is positioned in the tubular body each in a respective plane perpendicular to the longitudinal axis. The mounting surfaces face toward each other in opposite directions. The compressible framework extends between the first and second mounting surfaces. The spring assembly can further include a pair of electrical circuits mounted to the pair mounting surfaces. Each electrical circuit can include an inductive coil such that the pair of electrical circuits is a distance transducer. A change in distance between the pair of electrical circuits can be detected when the compressible framework is compressed and/or bent.