Segmented Medical Lead Body Stiffness for Coronary Vein Fixation
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Solution Overview
Problem
Existing medical electrical leads face challenges in navigating and fixing electrodes within the coronary venous vasculature to achieve stable electrical contact with surrounding tissue, particularly for left ventricular pacing, due to anatomical and conduction characteristic issues.
Innovation Solution
The design of a medical electrical lead with a multiconductor coil lead body featuring pre-formed arcuate segments and varying stiffness sections, allowing for flexible insertion and fixation within the coronary vein, with optional fixation members to ensure stable contact and reduced stimulation thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a lead with rigid structure is used, then fixation stability is improved, but electrode contact with surrounding tissue deteriorates
Solution Approach 1:
The lead body is divided into multiple segments with different stiffness characteristics. The proximal segment has higher stiffness for stable fixation, while the distal segment has lower stiffness to conform to the coronary vein wall and ensure good electrode contact. This segmentation allows each portion to perform its specific function optimally.
Solution Approach 2:
Different portions of the lead body are assigned different mechanical properties (stiffness). The proximal portion is made stiffer for anchoring stability, while the distal portion is made more flexible to adapt to the curved vein wall. This local differentiation resolves the contradiction between overall stability and local contact quality.
2Ease of manufacture
If a lead with uniform stiffness is used, then manufacturing is simplified, but ability to conform to coronary vein geometry deteriorates
Solution Approach 1:
The lead body is segmented into multiple portions with progressively different stiffness characteristics from proximal to distal. This segmentation enables the lead to conform to the curved geometry of the coronary vein while maintaining manufacturing feasibility through systematic property variation.
Solution Approach 2:
The stiffness parameter of the lead body is changed progressively from the proximal to the distal portion. This parameter variation allows the lead to adapt to the changing geometry requirements along its length, with the distal end being more flexible to match the vein's curvature.
3Ease of operation
If the lead is made more flexible for insertion, then navigation through coronary vein is improved, but fixation stability deteriorates
Solution Approach 1:
The lead is segmented such that the proximal portion maintains higher stiffness for stable fixation after insertion, while the distal portion is made more flexible to facilitate navigation and insertion through the coronary vein. This segmentation allows the lead to exhibit different mechanical properties at different locations.
Solution Approach 2:
Different local regions of the lead have different stiffness characteristics tailored to their specific functional requirements. The proximal end is stiffer for anchoring, while the distal end is more flexible for navigation, resolving the contradiction between insertion ease and fixation stability.
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A distal section of an implantable medical electrical lead body includes a pair of pre-formed arcuate segments between which an approximately straight segment extends. The approximately straight segment includes a first portion extending distally from a first of the pair pre-formed arcuate segments, a second portion extending from the first portion, a third portion extending from the second to a second of the pair pre-formed arcuate segments. An electrode is coupled to the second portion of the approximately straight segment, and the adjacent first portion has a stiffness which is less than that of the first of the pair pre-formed arcuate segments and preferably less than the stiffness of the third portion, so that, when the distal section of the lead body is implanted, for example, within a cardiac vein, the lead buckles to bring the electrode into closer contact with surrounding tissue.