Deformable Microlead for Deep Coronary Vein Stimulation
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Solution Overview
Problem
The challenge lies in ensuring permanent contact of electrodes with coronary veins and preventing displacement of active probe parts in the coronary venous network, particularly due to the small diameter of the probes and the instability caused by heart movements and anatomical features like anastomoses, which affects the effectiveness of cardiac stimulation.
Innovation Solution
A microprobe design featuring a distal active part with an insulating layer and stripped electrodes, a retention zone for mechanical stability, and an elongation zone that can absorb axial stresses without displacing the electrodes, ensuring stable positioning and contact with the venous wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the diameter of the probe is reduced to enable cannulation of narrow coronary veins, then the ability to access deep coronary network and multiply stimulation points is improved, but the stability of electrode contact with the vein wall deteriorates
Solution Approach 1:
The probe is divided into functionally distinct segments: a distal active part with electrodes for stimulation, a retention zone with anchoring elements for stability, and a proximal part for connection. This segmentation allows the thin distal end to access narrow veins while the retention zone provides stable contact through dedicated anchoring structures.
Solution Approach 2:
The retention zone acts as an intermediary element between the thin active part and the vein wall. It includes features such as helical reliefs and anchoring elements that mediate the connection, providing stable contact and preventing displacement without requiring the entire probe to be thick.
2Length of moving object
If the probe diameter is reduced to avoid blood flow obstruction, then the irrigation of downstream venous network is improved, but the mechanical holding capability in the vein deteriorates
Solution Approach 1:
The probe structure separates the functions of blood flow passage and mechanical retention. The thin distal active part maintains blood flow by minimizing obstruction, while the dedicated retention zone with helical reliefs and anchoring elements provides the necessary mechanical holding capability through localized structural features.
Solution Approach 2:
The probe exhibits local quality variations along its length: the distal active part has minimal diameter for blood flow preservation, while the retention zone features increased diameter and specialized structures (helical reliefs, anchoring elements) for mechanical holding. This localized differentiation allows simultaneous optimization of both blood flow and retention.
3Adaptability or versatility
If the probe is made flexible to navigate coronary venous network, then the ability to reach target veins and pass through anastomoses is improved, but the stability of probe position and electrode contact deteriorates
Solution Approach 1:
The probe is segmented into a flexible distal active part for navigation and a retention zone with anchoring features for stability. The flexible microcable construction with multiple strands allows navigation through complex venous pathways, while the retention zone with helical reliefs and anchoring elements provides position stability once deployed.
Solution Approach 2:
The probe incorporates dynamic characteristics through its flexible microcable construction that allows movement and adaptation during insertion, while the retention zone features (helical reliefs, anchoring elements) provide dynamic anchoring that maintains stability against cardiac movements and physiological stresses.
4Length of moving object
If the active part of the probe is made very thin to access deep coronary zones, then the ability to cannulate narrow veins is improved, but the risk of electrode displacement due to heart movements increases
Solution Approach 1:
The probe separates the thin active part designed for accessing narrow deep coronary veins from a dedicated retention zone with helical reliefs and anchoring elements. This segmentation allows the active part to maintain minimal diameter for vein access while the retention zone provides robust anchoring that counteracts electrode displacement from heart movements.
Solution Approach 2:
The retention zone with its helical reliefs and anchoring elements serves as an intermediary that secures the thin active part in place. It mediates between the fragile thin microcable and the dynamic cardiac environment, providing stable anchoring that prevents electrode displacement while allowing the active part to remain thin for deep vein access.
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 microprobe achieves stable electrode contact and retention within the coronary veins, maintaining effective cardiac stimulation despite anatomical challenges and patient movements, thereby enhancing the reliability of heart resynchronization.
Implementation Method 1
an elongation zone, located in a proximal position with respect to the retention zone at a distance from the latter of between 5 and 150 mm and defined by a shaped region of the microprobe capable of making the latter elastically deformable in the longitudinal direction under the effect of an axial tensile/compressive stress
Data Source
Figure 1~2
Figure 3~10
AI summary
The microlead has a distal portion formed by an active microcable (14). A stimulation zone (ZS) is placed at a distal end of the microcable. A retention zone (ZR) comprises shape formed to abut a wall of a target vessel. A stretching zone (ZEL) is defined by a shaped region to provide elastic deformability along longitudinal direction under effect of axial tension/compression stress exerted on the microlead, where the axial traction/compression stiffness of the stretching zone is less than axial traction/compression/stiffness of the retention zone and stimulation zones.