Unipolar Electrogram Feature Extraction for Scar Tissue Detection

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Solution Overview

Problem

Current methods for identifying myocardial scar tissue in cardiac pacing require costly imaging procedures, which may not be readily available, making it challenging to select appropriate pacing sites for cardiac resynchronization therapy without accurate substrate identification.

Innovation Solution

A medical device system with an implanted lead and processor that senses heart activity to produce unipolar electrogram waveforms, extracts features such as peak amplitude, Q-wave negativity, and fractionation, and detects scar tissue based on these features to guide pacing therapy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If imaging procedures such as MRI are used to identify scar tissue, then the location of scar tissue can be accurately determined, but the cost increases and availability decreases

Engineering Contradiction:
Improvescar tissue location identification accuracyVSAvoidimaging system complexity and cost
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical imaging systems (MRI, CT) with an electrical field-based sensing system using unipolar electrograms. The sensing module records electrical signals from the heart, and a processor analyzes these signals to identify scar tissue, substituting expensive mechanical imaging with a simpler electrical measurement approach that uses the heart's own electrical activity as the sensing mechanism

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

Solution Approach 2:

The patent introduces unipolar electrogram signals as an intermediary between the heart tissue and the detection system. These electrograms serve as a mediator that carries information about scar tissue characteristics without requiring direct imaging of the tissue structure, allowing indirect detection of scar location through electrical signal analysis

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If imaging procedures are used to identify scar tissue, then appropriate pacing sites can be selected, but the procedure becomes less accessible in some geographic areas

Engineering Contradiction:
Improvepacing site selection reliabilityVSAvoidprocedure accessibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces inaccessible centralized imaging infrastructure with a portable, implantable sensing system that can be deployed anywhere. The unipolar electrogram sensing and analysis system requires no external imaging equipment or specialized facilities, making reliable scar tissue identification accessible in any geographic location where basic cardiac electrophysiology testing can be performed

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

Solution Approach 2:

The system uses the heart's own electrical activity to provide self-diagnostic information about scar tissue location. The unipolar electrograms are generated intrinsically by the heart tissue itself, and the analysis of these signals provides self-contained information about substrate health without requiring external imaging services or infrastructure

Inventive Principle:
Principle #25Self-service

3Measurement precision

If multiple EGM signal features are analyzed to detect scar tissue, then detection accuracy improves, but processing complexity increases

Engineering Contradiction:
Improvescar tissue detection accuracyVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the complex task of scar tissue detection into analysis of multiple distinct EGM signal features (amplitude, duration, morphology characteristics). Each feature is extracted and evaluated separately by the processor, allowing comprehensive assessment of scar tissue while breaking down the complex detection problem into manageable analytical components that can be processed systematically

Inventive Principle:
Principle #1Segmentation

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

Enables the identification of scar tissue without costly imaging, allowing for informed selection of pacing sites and improving the effectiveness of cardiac resynchronization therapy by avoiding scar tissue locations.

Implementation Method 1

a sensing module for sensing heart activity with the electrode to produce a unipolar electrogram (EGM) waveform

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3024384B1Identification of healthy versus unhealthy substrate for pacing from a multipolar lead
Publication Date: 2021.08.25 MEDTRONIC INC
  • EP3024384B1 patent drawingFigure 1
  • EP3024384B1 patent drawingFigure 2
  • EP3024384B1 patent drawingFigure 3

AI summary

A medical device system performs a method for determining presence of scar tissue through an implanted lead having an electrode for cardiac pacing and sensing. A sensing module senses heart activity with the electrode to produce a unipolar electrogram (EGM) waveform. A processor receives the unipolar EGM waveform and extracts two or more features representative of heart activity at the electrode. Scar tissue is identified at the site of the first electrode based upon at least two of the extracted features indicating scar tissue.