Sheath Conductive Perforations for Impedance Tracking
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Solution Overview
Problem
Existing impedance-based tracking systems for intrabody objects, such as catheters, face challenges in accurately determining the position of the sheath within the body, especially when the impedance-based tracking electrode is not aligned with conductive regions on the sheath.
Innovation Solution
The introduction of a guiding sheath with radial perforations or a conductive band near the distal end, which acts as a conductive conduit for electrical currents, allowing for impedance-based tracking without the need for active position sensors or electrical ports on the sheath.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If impedance-based tracking electrode is positioned within the sheath lumen, then the sheath can be tracked using impedance measurements, but accurate tracking cannot be achieved when the electrode is not aligned with conductive regions on the sheath
Solution Approach 1:
The sheath wall is configured with radial perforations that extend through the wall material, creating conductive pathways that allow electrical current to flow from the intracardiac electrode through the sheath wall to body surface electrodes, enabling accurate impedance-based tracking regardless of electrode position within the sheath lumen
Solution Approach 2:
The perforations in the sheath wall serve as an intermediary conductive pathway, allowing electrical current to traverse from the intracardiac electrode through the non-conductive sheath material to the body surface, thereby enabling indirect tracking of the sheath position
2Reliability
If the sheath wall is made non-conductive to isolate electrical signals, then signal interference is reduced, but impedance-based tracking becomes impossible
Solution Approach 1:
The sheath wall incorporates radial perforations that provide localized conductive pathways while maintaining overall non-conductive properties, allowing electrical current to flow through specific regions without creating widespread conductive paths that would compromise signal isolation
Solution Approach 2:
The sheath wall has different conductive properties in different regions: the bulk material remains non-conductive for signal isolation, while the perforated regions provide localized conductive pathways for impedance tracking, creating a spatially varying conductive structure
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 enables accurate visualization and tracking of the sheath's position within the body, improving the precision of catheter placement and navigation during medical procedures, such as electrophysiology mapping and ablation.
Implementation Method 1
the perforations act as a conductive conduit to an impedance-based tracking electrode... electrical currents injected from the catheter electrode will conduct primarily through the perforations
Data Source
AI summary
A sheath is presented having an electrically conducting region providing a low impedance path through the sheath wall. The electrically conducting region is configured to conduct electrical current between an impedance-based tracking electrode of an intralumenal catheter and body patch electrodes of an impedance-based tracking system when the impedance-based tracking electrode is adjacent the conducting region. The impedance-based tracking system is configured to determine a location of the electrically conducting region, and thereby the distal end of the sheath, based on ratios of electrical current at the body patch electrodes. The electrically conducting region can include irrigation perforations so that saline acts as an electrical conduit of the conducting region. Additionally, or alternatively, the electrically conducting region can include an electrically conductive material configured to act as an electrical conduit through the sheath wall.