CRM Lead Tip Coupler for Torque Consistency

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Solution Overview

Problem

Current cardiac rhythm management leads face challenges in efficiently extending and retracting fixation helices due to torque transmission issues, axial force misalignment, and friction, which affects the anchoring and stability of the leads within the heart.

Innovation Solution

The design incorporates a flexible insulative body with a terminal pin, a conductor member, a housing, and a coupler with bearing surfaces that facilitate rotational motion to extend and retract a fixation helix with minimal torque loss and misalignment, using a threaded interface to ensure precise alignment and reduce friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixation helix is used to anchor the lead within the heart, then tissue holding performance is improved, but torque transmission issues and axial force misalignment occur during extension and retraction

Engineering Contradiction:

Improvetissue holding performanceVSAvoidextension and retraction operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The lead assembly is segmented into distinct functional components: a fixation helix for anchoring, a coupler for motion conversion, a conductor member for torque transmission, and a terminal pin for operation. This segmentation allows each component to be optimized for its specific function while working together as an integrated system.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system employs dynamic motion conversion where rotational input at the terminal pin is transformed through the coupler into axial extension of the fixation helix, and vice versa for retraction. This dynamic transformation enables reliable anchoring while maintaining ease of operation through intuitive rotational movements.

Inventive Principle:

Principle #15Dynamics

2Productivity

If the coupler rotates in response to conductor member rotation, then torque is transmitted to extend the fixation helix, but torque loss and misalignment occur

Engineering Contradiction:

Improveextension and retraction efficiencyVSAvoidtorque loss

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The coupler acts as an intermediary mechanism between the conductor member and the fixation helix. It receives rotational motion from the conductor member and converts it to axial motion for helix extension, while its bearing surfaces minimize friction and torque loss during the transformation process.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the parameter of motion from rotational to axial through the coupler mechanism. The bearing surfaces are designed to facilitate this parameter change with minimal energy loss, maintaining high torque transmission efficiency throughout the extension and retraction cycles.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If bearing surfaces are added to the coupler to reduce friction, then torque transmission is improved, but device complexity increases

Engineering Contradiction:

Improvetorque transmission reliabilityVSAvoidcoupler structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The bearing surfaces are merged into the coupler structure itself rather than being separate components. The coupler incorporates both the motion conversion function and the low-friction bearing surfaces in a single integrated element, reducing overall device complexity while maintaining reliable torque transmission.

Inventive Principle:

Principle #5Merging (Combining)

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

This configuration enhances the ability to securely anchor the lead within the heart by minimizing torque loss and misalignment, facilitating reliable extension and retraction of the fixation helix with improved tissue holding performance.

Implementation Method 1

The rear bearing surface and the front bearing surface are configured to facilitate linear motion of the coupler within the housing in response to rotation of the conductor member

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

using a threaded interface to ensure precise alignment and reduce friction

Methodology Applied

Scientific EffectThreaded mechanism: Screw

Data Source

PatentUS11712556B2Extendable/retractable active fixation CRM lead tip design for turn count consistency

Publication Date: 2023.08.01 CARDIAC PACEMAKERS INC

AI summary

Various aspects of the present disclosure are directed toward apparatuses, systems, and methods that include an implantable lead having a terminal pin, a conductor member configured to rotate in response to rotation of the terminal pin and a coupler arranged within configured to interface with the conductor member and having a rear bearing surface contacting the inner wall of a housing.