Implantable Medical Lead Inflatable Shield for Field Direction

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Solution Overview

Problem

Implantable medical leads used in cardiac systems often require higher energy levels for pacing and defibrillation when electrodes are positioned extravascularly, leading to unintended stimulation of extracardiac tissues such as the phrenic nerve or intercostal nerves.

Innovation Solution

The use of implantable medical leads with expandable shields configured to impede the electric field away from the heart, reducing the likelihood of stimulating unintended tissue and allowing for lower energy electrical therapies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If higher energy levels are used for pacing and defibrillation with extravascular electrodes, then cardiac capture and defibrillation effectiveness is improved, but unintended stimulation of extracardiac tissues such as the phrenic nerve or intercostal nerves occurs

Engineering Contradiction:

Improvecardiac capture effectivenessVSAvoidunintended stimulation of extracardiac tissues

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A shield member is introduced as an intermediary component between the electrode and the extracardiac tissues. The shield selectively blocks electrical fields in directions away from the heart while allowing effective cardiac stimulation, thereby mediating between the need for high energy cardiac capture and the need to prevent harmful stimulation of surrounding nerves and tissues

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The shield provides directional selectivity by having different electrical field blocking properties in different spatial directions. It blocks fields in directions away from the heart (posterior, lateral) while permitting fields to effectively stimulate cardiac tissue (anterior, superior, inferior directions), creating local quality differences in electrical field distribution

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If electrodes are positioned extravascularly, then surgical risk is reduced, but higher energy levels are required for effective cardiac capture

Engineering Contradiction:

Improvesurgical riskVSAvoidenergy level for pacing and defibrillation

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The shield acts as a mediator that enables extravascular electrode positioning to be effective. By directing and concentrating the electrical field toward the heart while blocking dispersion in other directions, the shield allows extravascular placement (reducing surgical risk) to achieve cardiac capture at lower energy levels than would otherwise be required

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If higher energy pacing pulses are delivered, then cardiac capture reliability is improved, but power source consumption increases and service life decreases

Engineering Contradiction:

Improvepacing capture reliabilityVSAvoidservice life of implantable cardioverter defibrillator

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The shield serves as a field-directing intermediary that improves pacing efficiency. By concentrating electrical energy toward the heart and preventing dispersion into surrounding tissues, the shield enables reliable cardiac capture at lower energy levels, thereby reducing power consumption and extending the service life of the implantable cardioverter defibrillator battery

Inventive Principle:

Principle #24Intermediary (Mediator)

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 shields effectively reduce the risk of stimulating extracardiac tissues, enable lower energy pacing pulses, and prolong the service life of implantable cardioverter defibrillators (ICDs) by minimizing power consumption.

Implementation Method 1

conventional pace electrodes placed extravascularly may direct a significant portion of the electrical field produced by a pacing pulse away from the heart

Methodology Applied

Scientific EffectElectric field: Electric Field

Data Source

PatentUS20250186788A1Implantable medical lead with shield

Publication Date: 2025.06.12 MEDTRONIC INC

AI summary

An example impkintable medical lead includes a first defibrillation electrode and a second, defibrillation electrode, the first and second, defibrillation electrodes configured to deliver first electrical therapy comprising anti tachyarrhythmia shocks. The implantable medical lead also includes a pace electrode disposed longitudinally between the first defibrillation electrode and the second defibrillation electrode, the pace electrode configured to deliver a pacing pulse that generates an electric field proximate to the pace electrode. The implantable medical lead further includes an inflatable shield disposed over a portion of an outer surface of the pace electrode, wherein the inflatable shield is configured to extend laterally away from the pace electrode upon inflation, wherein the inflatable shield is configured to impede an electric field of at least, one of the first and second the electrical therapies in a direction away from a heart of the patient.