ECG Artifact Filtering via Time Domain Modeling

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Solution Overview

Problem

Current CPR methods require interruptions to assess heart rhythm, which can be detrimental to patient survival due to the interference of chest compressions with ECG recordings, making it difficult to interpret ECG data and determine the need for defibrillation therapy during continuous chest compressions.

Innovation Solution

A method and system for processing ECG waveform data by sensing and filtering out physical non-cardiac influences such as chest compressions using a time domain computer model, allowing for continuous ECG monitoring without interruptions, involving adaptive filtering and impedance measurements to remove artifacts caused by chest compressions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If chest compressions are performed during CPR, then blood flow to vital organs is provided, but ECG recordings become difficult to interpret due to artifacts

Engineering Contradiction:

Improveblood flow provisionVSAvoidECG recording accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the ECG signal processing into multiple stages: raw signal acquisition during compressions, artifact detection and modeling, adaptive filtering to separate artifacts from cardiac signals, and reconstruction of clean ECG waveforms. This segmentation allows continuous compressions while maintaining ECG interpretation capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary processing system that acts as a mediator between the chest compressions and ECG recording. The adaptive filter serves as an intermediary that mathematically separates the compression artifacts from the underlying cardiac signals, allowing both functions to coexist without direct interference.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If CPR compressions are interrupted to obtain accurate ECG recordings, then ECG interpretation becomes possible, but patient survival is detrimentally affected

Engineering Contradiction:

ImproveECG recording accuracyVSAvoidpatient survival rate

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent performs preliminary action by pre-characterizing the artifact patterns generated by chest compressions through modeling and adaptive filtering. By establishing the artifact model before it corrupts the ECG signal, the system can continuously remove artifacts in real-time, eliminating the need to interrupt compressions for signal acquisition.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent enables continuous action by maintaining uninterrupted chest compressions while continuously applying adaptive filtering to the ECG signal. The useful action of blood flow provision through compressions continues without interruption, while the ECG monitoring function is simultaneously maintained through real-time artifact removal.

Inventive Principle:

Principle #20Continuity of useful action

3Productivity

If adaptive filtering is applied to remove chest compression artifacts, then continuous ECG monitoring is enabled, but computational complexity increases

Engineering Contradiction:

Improvecontinuous monitoring capabilityVSAvoidsignal processing complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent employs dynamic adaptive filtering where the filter parameters continuously adjust based on the incoming signal characteristics. The adaptive nature allows the system to track changing compression patterns and artifact levels in real-time, enabling continuous monitoring without requiring fixed, overly complex preprocessing.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements feedback mechanisms where the filtered ECG signal is continuously monitored and used to adjust the artifact modeling and filtering parameters. This closed-loop approach allows the system to self-optimize the filtering complexity based on actual signal conditions, preventing unnecessary computational overhead.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11129560B2Systems and methods for filtering ECG artifacts

Publication Date: 2021.09.28 ZOLL MEDICAL CORPORATION

AI summary

Systems and methods of processing raw electrocardiogram (ECG) waveform data of a patient into estimated real-time ECG waveform data. The method includes sensing at least one physical non-cardiac influence on the raw ECG waveform data, constructing a time domain computer model of the at least one physical, non-cardiac influence on the raw ECG waveform data, and adaptively filtering the raw ECG waveform data in the time domain using the constructed time domain computer model of the at least one physical non-cardiac influence on the raw ECG waveform data to form the estimated real-time ECG waveform data. The system can include an ECG device for collecting raw ECG waveform data, at least two ECG electrodes positioned on the patient and electrically coupled to the ECG device, and a processor coupled to the ECG device and configured to compute a time domain model of an artifact created by chest compressions.