Expandable Catheter Stiffness Control for Precise Cardiac Tissue Contact
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Solution Overview
Problem
Existing catheters used for cardiac electrophysiology procedures face challenges in precise control and adaptation to varying tissue configurations, requiring improved navigation and contact with cardiac tissue for effective mapping and therapy.
Innovation Solution
An expandable structure with adjustable stiffness, controlled by a deflection control member and selective movement limiter, allows for precise positioning and contact with cardiac tissue, facilitated by an electric-field-based or magnetic-field-based positioning system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the catheter uses a fixed stiffness structure, then the manufacturing is simpler, but the adaptability to varying tissue configurations is reduced
Solution Approach 1:
The catheter incorporates a deflection control member that can be selectively positioned to change the stiffness of the expandable structure. This dynamic adjustment mechanism allows the catheter to adapt to different tissue configurations by modifying its mechanical properties during the procedure, resolving the contradiction between adaptability and structural simplicity.
Solution Approach 2:
The catheter enables changes in the stiffness parameter of the expandable structure through the deflection control member. By altering this mechanical parameter, the catheter can better accommodate varying tissue configurations while maintaining a relatively simple base structure, thus improving adaptability without proportionally increasing complexity.
2Measurement precision
If the catheter uses an expandable structure with adjustable stiffness, then the precision of tissue contact is improved, but the device complexity increases
Solution Approach 1:
The catheter is divided into functional segments including the expandable structure, deflection control member, and selective movement limiter. This segmentation allows each component to perform its specific function independently, improving tissue contact precision while keeping the overall complexity manageable through modular design.
Solution Approach 2:
The deflection control member acts as an intermediary element between the user and the expandable structure. It provides a simplified interface for controlling the stiffness adjustment, thereby improving precision of tissue contact without requiring the user to directly manage the complex expandable mechanism.
3Ease of operation
If the deflection control member is made freely movable, then the ease of operation is improved, but the control precision over the expandable structure is reduced
Solution Approach 1:
The selective movement limiter provides feedback to the deflection control member by limiting its movement to specific ranges. This feedback mechanism maintains ease of operation while ensuring precise control over the expandable structure's stiffness, as the limiter guides the deflection control member to appropriate positions.
Solution Approach 2:
The selective movement limiter applies different constraints to different portions of the deflection control member's movement. It allows freedom of movement in certain directions while restricting movement in others, thereby maintaining ease of operation for intuitive control while achieving precise stiffness adjustment through localized constraint.
Data Source
AI summary
Elongate medical devices with an expandable structure including elongated splines and a distal hub. An elongate medical device includes a handle including a control mechanism, a catheter shaft, an expandable structure including elongated splines and a distal hub, wherein each of the elongated splines includes a shape memory material and an interactive element, wherein each of the elongated splines includes a respective spline proximal end and a spline distal end, wherein each of the spline proximal ends is connected to the catheter shaft distal end, and wherein each of the spline distal ends is connected to the distal hub, and a deflection control member connected to the distal hub, wherein the control mechanism is drivingly coupled to the distal hub via the deflection control member and operable to selectively vary a position of the distal hub relative to the catheter shaft distal end to selectively vary an amount of expansion of the expandable structure, wherein a shape of the expandable structure is produced via a combination of the shape memory material and the position of the distal hub relative to the catheter distal end.