Leadless Cardiac Pacemaker Backup Fixation Against Migration
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Solution Overview
Problem
Conventional cardiac pacemakers face issues such as bulging, erosion, infection, and detachment of leadless pacemakers from the heart, posing risks of device loss in the vasculature, which existing primary fixation methods fail to adequately address.
Innovation Solution
The implementation of a leadless cardiac pacemaker with both primary and secondary fixation elements, including active and passive forms, such as tines, hooks, and expandable structures, to secure the device within the heart chamber and prevent dislodgement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If primary fixation elements are used to secure the leadless pacemaker to the heart wall, then the device is anchored in place, but the device may become dislodged and migrate downstream into the vasculature
Solution Approach 1:
The patent incorporates secondary fixation elements (such as tines, hooks, or expandable structures) that remain dormant during normal operation but activate automatically if the primary fixation fails. These elements provide a backup retention mechanism that prevents downstream migration into the vasculature, thus cushioning against the harmful effect of device loss before it can occur.
Solution Approach 2:
The fixation elements are designed to change their mechanical parameters (such as expansion state or engagement configuration) in response to dislodgement forces. When the pacemaker attempts to migrate, the secondary fixation elements transition from a low-profile state to an engaged state, increasing their retention force to counteract the migration and prevent entry into downstream vessels.
2Reliability
If secondary fixation elements are added to prevent dislodgement, then device retention is improved, but device complexity increases
Solution Approach 1:
The patent integrates secondary fixation elements into the same housing structure that contains the primary fixation elements, merging multiple retention functions into a single unified device. This consolidation reduces the number of separate components and simplifies the overall device architecture while maintaining dual fixation capabilities.
Solution Approach 2:
The secondary fixation elements are designed to serve multiple purposes: they provide backup retention, assist in device retrieval, and can be configured to engage different tissue structures. This multi-functionality reduces the need for separate dedicated components for each function, thereby managing device complexity while enhancing reliability.
3Reliability
If fixation elements engage heart tissue, then the pacemaker is securely anchored, but retrieval becomes more difficult
Solution Approach 1:
The fixation elements are designed with dynamic characteristics that allow them to engage heart tissue firmly during normal operation but to be actively disengaged when needed. The secondary fixation elements, in particular, can be controlled to deploy or retract, enabling secure anchoring during use while facilitating controlled retrieval when the device needs to be removed or repositioned.
Solution Approach 2:
The patent incorporates a retrieval mechanism that can actively disengage and extract the fixation elements from the heart tissue. This extraction capability allows the device to be removed cleanly without causing tissue damage, effectively reversing the anchoring action and solving the retrieval difficulty while maintaining secure anchoring during normal operation.
Data Source
AI summary
The invention relates to leadless cardiac pacemakers (LBS), and elements and methods by which they affix to the heart. The invention relates particularly to a secondary fixation of leadless pacemakers which also include a primary fixation. Secondary fixation elements for LBS's may passively engage structures within the heart. Some passive secondary fixation elements entangle or engage within intraventricular structure such as trabeculae carneae. Other passive secondary fixation elements may engage or snag heart structures at sites upstream from the chamber where the LBS is primarily affixed. Still other embodiments of passive secondary fixation elements may include expandable structures.