Catheter Shaping Wire Torque Transfer via Non-Circular Cross-Section
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Solution Overview
Problem
Existing electrophysiology catheters face challenges in precisely placing the looped section within the pulmonary vein ostia due to varying patient anatomies, requiring improved torque strength and rotation capabilities.
Innovation Solution
A catheter design featuring a shaping wire with a distal circular cross-sectional shape transitioning to a non-circular proximal cross-sectional shape, promoting 1:1 torque transfer and increased bonding surface area, allowing for a partial loop of fixed or variable radius to conform to the pulmonary vein ostia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a circular shaping wire is used throughout the catheter, then the catheter can be easily manufactured, but torque transfer from the proximal region to the distal region is insufficient for precise loop placement
Solution Approach 1:
The shaping wire transitions from a circular cross-section in the distal region to a non-circular cross-section in the proximal region. This local variation in geometry optimizes torque transfer properties where needed (proximal region) while maintaining manufacturing simplicity (circular distal region), directly resolving the contradiction between torque strength and device complexity.
Solution Approach 2:
The patent introduces asymmetry by using a non-circular cross-section for the proximal portion of the shaping wire. This asymmetric geometry provides enhanced torque transfer characteristics compared to a symmetric circular cross-section, enabling precise loop placement while accepting increased structural complexity only where necessary.
2Adaptability or versatility
If the loop radius is made variable to adapt to varying patient anatomies, then the catheter can accommodate different pulmonary vein ostia sizes, but the complexity of the shaping wire increases
Solution Approach 1:
The patent implements a dynamic loop structure where the radius of curvature can vary along the distal region of the catheter body. This dynamic geometry allows the loop to adapt to different pulmonary vein ostia sizes and anatomical variations, while the variation is achieved through controlled changes in the shaping wire geometry rather than complex mechanical adjustment mechanisms.
Data Source
AI summary
A catheter has a body including a proximal region, a neck region, and a distal region. A shaping wire is disposed within the distal region to predispose it into at least a partial loop, which may have a fixed or variable radius of curvature. The shaping wire includes a distal portion having a circular transverse cross-sectional shape and a proximal portion having a non-circular (e.g., rectangular) transverse cross-sectional shape. The proximal portion of the shaping wire can have a width-to-thickness ratio of at least about 4, such as about 4.67. A transition portion can promote a gradual transition from the circular to the non-circular transverse cross-sectional shape, for example by increasing a width of the shaping wire by about 0.001″ and/or by decreasing a thickness of the shaping wire by about 0.001″ for every about 0.004″ in length through the transition portion.