Active Fixation Lead Coupling Assessment via Electrical Impedance

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Solution Overview

Problem

Conventional methods for assessing the coupling of leads to tissue, such as fluoroscopic imaging, are subjective and expose patients and clinicians to radiation, while also potentially reducing the useful life of medical devices due to improper placement.

Innovation Solution

A system and method using capacitance, inductance, voltage, or current measurements between an electrode and a fixation element to assess the coupling of a lead to tissue, providing a measurable and less subjective evaluation, thereby minimizing the need for fluoroscopic imaging and reducing radiation exposure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If fluoroscopic imaging is used to assess lead coupling, then placement can be visualized, but radiation exposure increases and assessment becomes subjective

Engineering Contradiction:
Improveassessment objectivityVSAvoidradiation exposure
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical/optical fluoroscopic imaging system with an electrical measurement system. Instead of using X-rays to visualize lead placement, the invention uses electrical impedance measurements between the lead electrode and reference electrode to objectively assess coupling. This substitution eliminates radiation exposure while providing quantifiable, objective data about lead-tissue coupling through electrical properties rather than visual imaging.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces electrical impedance as an intermediary parameter to assess lead coupling. Rather than directly observing lead placement through fluoroscopy, the system measures the electrical impedance between the lead electrode and reference electrode, which serves as a mediator that correlates with coupling quality. This intermediary measurement provides objective, quantifiable information without requiring direct visual observation or radiation exposure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If fluoroscopic imaging is used to assess lead coupling, then placement can be visualized, but the assessment becomes subjective

Engineering Contradiction:
Improveassessment objectivityVSAvoidimaging system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the complex fluoroscopic imaging system with a simpler electrical measurement system. Instead of requiring X-ray generation, imaging detectors, and image processing infrastructure, the invention uses basic electrical impedance measurement circuits that are already present in most implantable pulse generators. This substitution dramatically reduces system complexity while improving assessment objectivity through quantitative electrical measurements.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the essential assessment function from the complex fluoroscopic imaging system. Rather than using the entire imaging infrastructure, the invention isolates and measures only the electrical impedance parameter that is relevant to lead coupling assessment. This extraction of the critical measurement function eliminates the need for complex imaging equipment while maintaining assessment capability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If lead placement is not optimal, then device placement is quick, but device useful life is reduced

Engineering Contradiction:
Improveplacement speedVSAvoiddevice useful life
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements immediate feedback about lead coupling quality through electrical impedance measurements. During the placement procedure, the system continuously or periodically measures impedance between the lead electrode and reference electrode, providing real-time information about coupling quality. This feedback allows the operator to adjust lead placement immediately if coupling is insufficient, ensuring optimal placement before device activation and thereby maximizing device useful life without sacrificing placement speed.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary assessment of lead coupling using electrical impedance measurements before final device activation. The system evaluates coupling quality in advance through impedance characterization, allowing optimization of lead placement before the device begins its intended function. This preliminary action ensures that suboptimal placements are corrected before they can compromise device longevity, while maintaining efficient placement procedures.

Inventive Principle:
Principle #10Preliminary action

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 approach offers a more objective assessment of lead-tissue coupling, reducing radiation exposure and ensuring optimal device placement, which can extend the useful life of medical devices and improve diagnostic and treatment efficacy.

Implementation Method 1

the use of the capacitance, inductance, voltage or current between the electrode and fixation element provides a measurable quantity indicative of the relative locations of the electrode and fixation element and the degree of coupling of the fixation element to tissue

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

the use of the capacitance, inductance, voltage or current between the electrode and fixation element provides a measurable quantity indicative of the relative locations of the electrode and fixation element and the degree of coupling of the fixation element to tissue

Methodology Applied
Scientific EffectInductance: Inductor

Data Source

PatentEP2470070B1Electrical metering of active fixation lead coupling
Publication Date: 2016.04.20 ST JUDE MEDICAL ATRIAL FIBRILLATION DIVISION INC
  • EP2470070B1 patent drawingFigure 1
  • EP2470070B1 patent drawingFigure 2~3
  • EP2470070B1 patent drawingFigure 4

AI summary

A system (10) and method for assessing coupling of a lead (12) to tissue (14) are provided. The inventive system (10) includes a lead body (24) with an electrode (30) and a fixation element (32) disposed near a distal end (28) of the lead body (24). The fixation element (32) is configured to anchor the distal end (28) of the lead body (24) in the tissue (14). The system (10) further includes a meter (18) configured to generate a signal indicative of an amount of energy between the electrode (30) and the fixation element (32). The amount of energy may comprise capacitance or inductance between the electrode (30) and the fixation element (32). The system (10) further includes an electronic control unit (20) configured to determine a degree of coupling between the lead (12) and the tissue (14) responsive to the signal.