Coaxial Fixation Elements for Leadless Pacemaker Tissue Anchoring
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Solution Overview
Problem
Existing leadless cardiac pacemakers face challenges with anchor damage to tissue over time and ineffective long-term securing of the device, leading to reliability issues.
Innovation Solution
A biostimulator with coaxial fixation elements, including an outer and inner helix, where the outer fixation element is less stiff than the inner element, allowing for secure engagement and retention of the biostimulator to the target tissue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single anchor is used to secure the leadless cardiac pacemaker, then the device can be implanted, but the anchor may damage the target tissue over time or fail to securely secure the device, leading to reliability issues
Solution Approach 1:
The fixation system is divided into multiple separate fixation elements (first fixation element and second fixation element) that engage the tissue at different locations. This segmentation distributes the mechanical stress and anchoring force across multiple tissue engagement points, preventing any single anchor from causing excessive tissue damage while collectively providing secure long-term device retention.
2Reliability
If conventional anchors are used, then the device can be anchored, but they may ineffectively secure the leadless cardiac pacemaker to the target tissue over time
Solution Approach 1:
The fixation system uses multiple fixation elements positioned at different locations on the device housing, each independently engaging the target tissue. This multi-point fixation approach distributes mechanical loads and prevents single-point failure, ensuring that the device remains securely anchored to the tissue over extended periods even if one fixation element experiences stress or degradation.
Solution Approach 2:
The fixation elements are configured where the second fixation element is positioned relative to the first fixation element in a nested or offset arrangement along the longitudinal axis. This spatial configuration allows both fixation elements to engage tissue at different depths or locations simultaneously, creating a layered anchoring system that enhances long-term security without interfering with each other's function.
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
The coaxial fixation elements provide reliable long-term anchoring, reducing the likelihood of disengagement and enhancing the stability of the biostimulator within the tissue.
Implementation Method 1
The outer fixation element may be less stiff than the inner fixation element, e.g., along the longitudinal axis. When the outer fixation element engages tissue, it can compress axially to bring the inner fixation element into tissue contact.
Data Source
AI summary
A biostimulator, such as a leadless cardiac pacemaker, including coaxial fixation elements to engage or electrically stimulate tissue, is described. The coaxial fixation elements include an outer fixation element extending along a longitudinal axis and an inner fixation element radially inward from the outer fixation element. One or more of the fixation elements are helical fixation elements that can be screwed into tissue. The outer fixation element has a distal tip that is distal to a distal tip of the inner fixation element, and an axial stiffness of the outer fixation element is lower than an axial stiffness of the inner fixation element. The relative stiffnesses are based on one or more of material or geometric characteristics of the respective fixation elements. Other embodiments are also described and claimed.