Catheter Loop Contraction via Radially-Constrictive Sleeve
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Solution Overview
Problem
Current catheters for invasive medical treatments, particularly those used for cardiac arrhythmia treatment, face challenges in accommodating varying human anatomy, maintaining a circular configuration during loop contraction, and ensuring reliable attachment of contraction wires to support members.
Innovation Solution
The development of a catheter with a variable arcuate distal section that incorporates a shape-memory support member, a contraction wire, and a radially-constrictive tubing to enhance contraction and bending radius characteristics, while ensuring durability and accurate circular loop formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a catheter uses a uniform cross-section support member for loop contraction, then the structure is simple to manufacture, but it fails to maintain a circular configuration during contraction and requires excessive contraction force
Solution Approach 1:
The support member transitions from a uniform cross-section to a variable cross-section design where the second moment of area changes along the length of the member. This local variation in structural properties allows different sections to contribute differently to loop contraction, enabling maintenance of a circular configuration while reducing the force required for contraction.
2Device complexity
If a catheter uses a uniform cross-section support member, then the structure is simple, but it requires more contraction wire tensile force for less loop contraction
Solution Approach 1:
The support member's cross-sectional properties are varied along its length, specifically changing the second moment of area from uniform to non-uniform distribution. This parameter change optimizes the mechanical characteristics of the support member, allowing for more efficient loop contraction with reduced tensile force requirements while maintaining structural integrity.
3Productivity
If a catheter uses a variable arcuate distal section with radially-constrictive tubing, then contraction efficiency is improved and force requirements are reduced, but the device complexity increases
Solution Approach 1:
The catheter employs a composite construction combining a variable cross-section support member with radially-constrictive tubing. This composite structure integrates multiple materials and design features to achieve superior contraction efficiency and circular configuration maintenance, with the complexity justified by the significant improvement in clinical performance and ease of operation.
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
This solution allows for improved maneuverability and positioning within the heart and tubular regions of varying sizes, enabling more effective ablation and mapping procedures with enhanced contraction efficiency and reduced force requirements.
Implementation Method 1
the support member is made of a shape-memory material, such as nitinol, and has a preformed, three-dimensional (3-D) configuration
Implementation Method 2
a radially-constrictive tubing or sleeve to greatly increase the degree of contraction of a generally circular catheter loop
Data Source
AI summary
A catheter with a variable circular loop is responsive to a contraction wire for increasing the coiling of the circular loop. The shape of the loop is supported by an elongated member, wherein a radially constrictive sleeve confines the contraction wire to extends immediately alongside the length of elongated member so as to improve uniformity and minimize misshaping of the loop during contraction.