Leadless Cardiac Device Fixation Tines for Tissue-Sparing Deployment
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Solution Overview
Problem
Traditional implantable cardiac pacemakers with elongate lead wires face mechanical complications and MRI compatibility issues, necessitating the development of compact devices that can be implanted near the pacing site without perforating surrounding tissues.
Innovation Solution
A compact implantable medical device with a fixation mechanism comprising a plurality of tines, each segment pre-formed to provide a spring-biased curvature, allowing for secure deployment and fixation within the heart without perforating the visceral pericardium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If traditional elongate lead wires are used in implantable cardiac pacemakers, then the device can be implanted remotely from the heart, but mechanical complications and MRI compatibility issues occur
Solution Approach 1:
The patent extracts and eliminates the elongate lead wire component from the traditional pacemaker system. The pulse generator is repositioned to be implanted in close proximity to the pacing site, removing the need for long lead wires that extend through veins to remote subcutaneous pockets, thereby eliminating the mechanical complications and MRI compatibility issues associated with lead wires
Solution Approach 2:
The patent merges the pulse generator with the pacing site location by implanting both in close proximity. The fixation mechanism with tines is integrated directly onto the pulse generator housing, combining the securing function with the device structure itself, eliminating the need for separate lead wire connections
2Reliability
If the device is implanted in close proximity to the pacing site, then lead wire-related complications are eliminated, but the device requires a fixation mechanism that prevents tissue perforation
Solution Approach 1:
The fixation mechanism is segmented into multiple independent tines (at least three) that are spaced around the perimeter of the pulse generator. Each tine can be independently configured with specific curvature and orientation, allowing the system to achieve stable fixation through the combined action of multiple simpler elements rather than one complex structure
Solution Approach 2:
The tines are configured with pre-formed curvatures including C-shaped and hook-shaped geometries. These curved configurations allow the tines to engage with tissue in a controlled manner, providing anchoring force while the rounded distal ends prevent perforation of the visceral pericardium
3Reliability
If tines are configured with spring-biased pre-formed curvature, then secure fixation is achieved without perforating tissue, but the tines require deformation control during deployment
Solution Approach 1:
The tines are pre-configured with spring-biased curvatures and orientations before deployment. The delivery tool is designed to maintain these tines in a constrained, straightened state during insertion. Upon deployment, the pre-formed curvatures automatically activate, causing the tines to assume their intended engaged configuration without requiring additional manipulation or control during the fixation process
Solution Approach 2:
A delivery tool with a tubular sidewall acts as an intermediary during deployment. The sidewall engages the distal ends of the tines, maintaining them in a straightened, constrained position during insertion. When the device is deployed, the tines are released from the delivery tool and automatically deform to their pre-formed curved configurations, achieving fixation without requiring direct manipulation
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 device achieves secure implantation near the pacing site with minimal tissue damage, ensuring effective fixation and compatibility with MRI procedures.
Implementation Method 1
a proximal spring portion (73) being fixedly attached to the base and having a spring-biased pre-formed curvature
Implementation Method 2
the first segment has a spring-biased pre-formed curvature, extending distally from the device distal end
Data Source
AI summary
A fixation mechanism of an implantable medical device is formed by a plurality of tines fixedly mounted around a perimeter of a distal end of the device. Each tine may be said to include a first segment fixedly attached to the device, a second segment extending from the first segment, and a third segment, to which the second segment extends. When the device is loaded in a lumen of a delivery tool and a rounded free distal end of each tine engages a sidewall that defines the lumen, to hold the tines in a spring-loaded condition, the first segment of each tine, which has a spring-biased pre-formed curvature, becomes relatively straightened, and the third segment of each tine, which is terminated by the free distal end, extends away from the axis of the device at an acute angle in a range from about 45 degrees to about 75 degrees.