Lead Impedance Trend Analysis for Insulation Breach Detection

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Solution Overview

Problem

Implantable medical devices face challenges in accurately sensing heart rhythms due to lead-related conditions such as insulation breaches, conductor fractures, and connector disruptions, which can lead to inappropriate therapy delivery and premature battery depletion.

Innovation Solution

A method for automatically identifying lead-related conditions through impedance measurement trends and oversensing parameters, using algorithms to detect short-term and long-term impedance trends, and determining the presence of oversensing criteria to prevent inappropriate therapy delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If lead bodies are made smaller and the number of lead conductors is increased, then device functionality is improved, but lead insulation integrity deteriorates

Engineering Contradiction:

Improvedevice functionalityVSAvoidlead insulation integrity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system performs preliminary detection of lead-related conditions by continuously monitoring impedance measurements and sensing waveforms before actual lead failure occurs. This early detection allows for preventive actions to be taken, resolving the contradiction by maintaining reliability through proactive monitoring while preserving the ability to use smaller, more functional leads.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system establishes a feedback loop by continuously measuring impedance, analyzing sensing waveforms for oversensing conditions, and using this information to predict lead-related conditions. This feedback mechanism maintains lead integrity monitoring without requiring larger or fewer conductors, thus preserving device functionality while improving reliability.

Inventive Principle:

Principle #23Feedback

2Device complexity

If lead-related conditions are not detected, then device simplicity is maintained, but inappropriate therapy delivery occurs

Engineering Contradiction:

Improvedevice simplicityVSAvoidtherapy delivery accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system enables the implantable medical device to self-diagnose lead-related conditions by automatically analyzing its own impedance measurements and sensing waveforms. This self-service capability detects oversensing and predicts lead conditions without requiring external intervention, maintaining device simplicity while ensuring reliable therapy delivery through automated monitoring.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system replaces complex mechanical diagnostic procedures with electrical impedance measurements and waveform analysis. By using electrical signals to detect lead conditions instead of mechanical testing, the system maintains simplicity while improving therapy delivery accuracy through continuous electronic monitoring.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If impedance measurements are continuously monitored, then lead condition detection accuracy is improved, but energy consumption increases

Engineering Contradiction:

Improvelead condition detection accuracyVSAvoidenergy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system performs impedance measurements and waveform analyses periodically rather than continuously, at predetermined time intervals. This periodic monitoring maintains lead condition detection accuracy by capturing changes over time while reducing energy consumption by allowing the device to operate in lower-power states between measurement cycles.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system applies partial monitoring by focusing impedance measurement analysis on specific parameters and time windows that are most indicative of lead conditions. By analyzing only the most relevant portions of the impedance data and sensing waveforms, the system maintains high detection accuracy while minimizing the total computational energy required.

Inventive Principle:

Principle #16Partial or excessive 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 reduces the risk of inappropriate therapy delivery, prolongs battery life, and enables early detection of lead-related issues, thereby improving the accuracy and reliability of heart rhythm sensing in implantable medical devices.

Implementation Method 1

a lead impedance measurement is made across the lead body at a first time

Methodology Applied

Scientific EffectElectrical Impedance: Electrical Resistance

Implementation Method 2

Such devices sense the heart's intrinsic rhythm through cardiac leads carrying electrodes

Methodology Applied

Scientific EffectElectrical Conduction: Conduction (electrical)

Data Source

PatentUS9561377B2Method and apparatus for identifying lead-related conditions using prediction and detection criteria

Publication Date: 2017.02.07 MEDTRONIC INC

AI summary

A method for delivering therapy in a medical device includes a two-tiered approach of determining the presence of a lead-related condition, and determining, in response to a lead-related condition being present, the presence of oversensing. Delivery of therapy by the medical device is controlled in response to determining that both the lead-related condition and oversensing are present.