Leadless Pacemaker Retrieval via Expandable Grasping Mechanism
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Solution Overview
Problem
There is a need for effective retrieval methods for leadless cardiac pacemakers implanted in the heart, as conventional retrieval systems are not suitable for these self-contained devices.
Innovation Solution
A retrieval system comprising a catheter with a grasping mechanism that expands to capture the docking member of the pacemaker, allowing it to be drawn into the catheter lumen, utilizing expandable structures such as inflatable balloons or resilient rings to securely engage and retract the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional pacemaker retrieval system is used, then the system structure is simple, but it cannot effectively retrieve leadless cardiac pacemakers from the heart
Solution Approach 1:
The retrieval system is divided into separate functional components: a retrieval device with a grasping mechanism, a catheter with a lumen, and a docking member on the pacemaker. This segmentation allows each component to be optimized for its specific function while maintaining overall system effectiveness in retrieving leadless pacemakers.
Solution Approach 2:
The docking member serves as an intermediary structure between the pacemaker and the retrieval device. It includes a head portion and neck portion that enables the grasping mechanism to capture and secure the pacemaker, facilitating effective retrieval without directly manipulating the pacemaker itself.
2Reliability
If the grasping mechanism is always expanded to capture the docking member, then the capture reliability is high, but the device cannot be delivered to the implantation site
Solution Approach 1:
The grasping mechanism is designed to be dynamically changeable between two states: an expanded state for capturing the docking member and a contracted state for delivery. This dynamic transformation allows the same mechanism to serve both delivery and capture functions effectively.
Solution Approach 2:
The grasping mechanism utilizes parameter changes in its radial dimension - expanding from a first radial dimension for delivery to a second, larger radial dimension for capture. This parameter change enables the mechanism to adapt its size and shape according to the operational requirement.
3Productivity
If the grasping mechanism is made expandable to capture the docking member, then the retrieval effectiveness is improved, but the device complexity increases
Solution Approach 1:
The grasping mechanism is designed to be self-actuating through balloon inflation. The balloon's expansion automatically causes the grasping mechanism to expand and capture the docking member without requiring external actuation, simplifying the control system while maintaining high retrieval effectiveness.
Solution Approach 2:
The grasping mechanism utilizes pneumatic principles through the inflatable balloon to achieve expansion and capture. The balloon's inflation provides the necessary force to expand the grasping mechanism's radial dimension, enabling effective capture of the docking member through a simple pneumatic action.
4Reliability
If the docking member has a large head portion for secure capture, then the capture stability is high, but the pacemaker cannot be implanted in the heart chamber
Solution Approach 1:
The docking member is segmented into two distinct portions: a head portion with a larger radial dimension for secure capture by the grasping mechanism, and a neck portion with a smaller radial dimension that allows passage through the heart chamber. This segmentation resolves the contradiction between capture stability and implantability.
Solution Approach 2:
The docking member utilizes dimensional variation along its length - the head portion has a larger radial dimension for capture stability, while the neck portion has a smaller radial dimension for navigation through the heart chamber. This dimensional change allows the same structure to satisfy both capture and implantation requirements.
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
Enables safe and efficient retrieval of leadless cardiac pacemakers from the heart by securely grasping and retracting the device, ensuring disengagement from cardiac tissue during removal.
Implementation Method 1
The grasping mechanism is expandable from a first position to a second position. The grasping mechanism is biased toward the first position in an equilibrium condition. The grasping mechanism is configured to surround and pass over the head portion of the docking member in the second position, and be contracted toward the first position to capture the docking member with the grasping mechanism.
Data Source
AI summary
A retrieval device and an associated implantable cardiac pacing device. The retrieval device includes a grasping mechanism configured to capture a docking member of the implantable cardiac pacing device to draw the implantable cardiac pacing device into the lumen of a retrieval catheter. The grasping mechanism is expandable from a first position to a second position and is biased toward the first position in an equilibrium condition. The grasping mechanism is configured to surround and pass over a head portion of the docking member in the second position, and be contracted toward the first position to capture the docking member with the grasping mechanism.