Baseline Electrode Impedance for Tissue Contact Detection

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Solution Overview

Problem

Existing methods for determining tissue contact using electrode impedances are hindered by variable baseline impedance values that need to be established for each electrode, making it difficult to accurately assess contact status due to patient-specific and procedure-specific variations, and the challenge of distinguishing between tissue contact and other factors affecting impedance.

Innovation Solution

A method and system that measure impedance values for each electrode, assign a baseline impedance value based on minimum impedance values within a predetermined interval, and determine a confidence value associated with this baseline, using bipolar electrode complex impedance (BECI) values to assess contact status when the confidence value meets a threshold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If baseline impedance values are determined for each electrode to enable tissue contact detection, then contact status can be assessed, but the high variability of baseline values across patients and procedures reduces measurement reliability

Engineering Contradiction:
Improvetissue contact detection accuracyVSAvoidbaseline impedance value consistency
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system performs preliminary actions by measuring impedance values over a predetermined time interval before正式 tissue contact detection, establishing a baseline that accounts for patient-specific and procedure-specific variations. This preliminary baseline determination reduces variability in subsequent measurements.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system determines a confidence value based on measured impedance values and uses this feedback to assess whether the baseline is reliable for tissue contact detection. The confidence value mechanism allows the system to evaluate and adjust baseline quality dynamically.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If impedance monitoring is used to detect tissue contact, then contact status can be determined, but other factors such as electrode location and tissue movement cause false variations in impedance readings

Engineering Contradiction:
Improvetissue contact detection accuracyVSAvoidinterference from electrode location and tissue movement
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system uses feedback by continuously monitoring impedance values and determining confidence values based on these measurements. This allows the system to distinguish between impedance changes caused by tissue contact versus those caused by other factors like electrode location or tissue movement.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes parameters by measuring impedance over a predetermined time interval and using the minimum impedance value as the baseline. This temporal parameter change allows the system to account for variations caused by electrode location and tissue movement while identifying true tissue contact events.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If a predetermined time interval is used to establish baseline impedance, then baseline values can be determined, but it is difficult to establish times when the electrode has been moved away from tissue

Engineering Contradiction:
Improvebaseline impedance determinationVSAvoidtime to establish reliable baseline
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system uses self-service by automatically determining baseline impedance values and confidence values without requiring manual intervention to establish when electrodes have been moved away from tissue. The predetermined time interval mechanism allows the system to self-establish baselines during normal operation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system performs preliminary impedance measurements over a predetermined time interval to establish baseline values before正式 tissue contact detection begins. This preliminary action ensures that baselines are determined efficiently without delaying the diagnostic process.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If confidence values are determined for baseline impedance values, then tissue contact detection reliability improves, but the system complexity increases

Engineering Contradiction:
Improvebaseline impedance value qualityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses feedback by determining confidence values based on measured impedance values and using this information to assess baseline quality for tissue contact detection. This feedback mechanism improves reliability without requiring complex external validation systems.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-service by automatically determining confidence values and assessing baseline quality without requiring manual verification or complex external systems. The confidence value mechanism is integrated into the existing impedance measurement framework.

Inventive Principle:
Principle #25Self-service

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 allows for the accurate determination of tissue contact status by stabilizing baseline impedance values and increasing confidence in their quality, reducing false positives and negatives, and ensuring reliable contact detection.

Implementation Method 1

measuring an impedance value of the first electrode generated in response to a drive signal to the first electrode

Methodology Applied
Scientific EffectElectrical Impedance: Electrical Resistance

Data Source

PatentEP4434453A1Method and system for determining baseline electrode impedance for tissue contact detection
Publication Date: 2024.09.25 ST JUDE MEDICAL CARDILOGY DIV INC
  • EP4434453A1 patent drawingFigure 1
  • EP4434453A1 patent drawingFigure 2
  • EP4434453A1 patent drawingFigure 3

AI summary

A method of determining a baseline impedance value for a first electrode in a plurality of electrodes located on a medical device for tissue contact detection includes measuring an impedance value of the first electrode generated in response to a drive signal to the first electrode. The method further includes assigning a baseline impedance value to the first electrode based on impedance values measured in a predetermined time interval and determining a confidence value associated with the baseline impedance value. The method further includes utilizing the baseline impedance value in determining contact status of the first electrode when the confidence value is at or above a predetermined threshold value.