ECG Lead Selection Using Signal-to-Noise Filtering

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Solution Overview

Problem

Existing ECG signal analysis systems face challenges in accurately identifying systolic intervals and cardiac conditions due to noise contamination from artifact signals, leading to false alarms and desensitization of clinicians, which can result in missing critical alerts.

Innovation Solution

An apparatus with processors configured to select sample points, extract features, and apply transformations to detect artifact signals, ensuring accurate identification of systolic intervals and cardiac conditions by applying algorithms to ECG signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If artifact detection and rejection algorithms are applied to ECG signals, then measurement precision of systolic intervals is improved, but device complexity increases

Engineering Contradiction:
Improveprecision of systolic interval identificationVSAvoidcomplexity of artifact detection system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The ECG signal processing is divided into multiple independent stages: initial QRS detection, artifact detection phase, artifact rejection phase, and final measurement phase. Each stage operates with simplified algorithms focused on specific tasks, avoiding the need for one complex algorithm to handle all aspects simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Artifact detection and rejection is performed as a preliminary step before final systolic interval measurement. By identifying and removing artifacts early in the processing chain, subsequent measurements operate on cleaner data, improving precision without requiring the final measurement algorithm to be overly complex.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If real-time artifact detection is implemented, then reliability of ECG analysis is improved, but processing time increases

Engineering Contradiction:
Improvereliability of cardiac signal analysisVSAvoidtime for signal processing
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The artifact detection algorithm focuses computational resources on local signal segments where artifacts are most likely to occur, such as regions with abnormal morphology or amplitude. Rather than uniformly processing the entire signal, the system applies enhanced detection only where needed, maintaining reliability while reducing overall processing time.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Complex iterative artifact detection algorithms are replaced with simplified threshold-based and morphological comparison methods. By substituting computationally intensive mechanical processing with lighter computational approaches, the system maintains reliability through pattern recognition while significantly reducing processing time.

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

3Loss of information

If multiple artifact sources are detected and rejected, then purity of ECG signal is improved, but false positive rate may increase

Engineering Contradiction:
Improvepurity of cardiac signalVSAvoidaccuracy of artifact identification
Core Design Contradiction:
Loss of informationVSMeasurement precision

Solution Approach 1:

The artifact detection system incorporates feedback mechanisms where detection results are validated against multiple criteria before rejection. The system monitors false positive rates and adjusts detection thresholds dynamically, using feedback from signal quality metrics to fine-tune artifact identification accuracy and minimize erroneous rejections of valid ECG components.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The detection algorithm dynamically adjusts parameters such as amplitude thresholds, morphological criteria, and detection sensitivity based on the specific characteristics of the incoming signal. By changing parameters adaptively rather than using fixed thresholds, the system improves signal purity through targeted artifact removal while maintaining accurate distinction between artifacts and genuine ECG features.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4424237B1Electrocardiogram ("ECG") signal analysis
Publication Date: 2025.11.26 DRAEGER MEDICAL SYSTEMS INC
  • EP4424237B1 patent drawingFigure 1
  • EP4424237B1 patent drawingFigure 2
  • EP4424237B1 patent drawingFigure 3A

AI summary

A method of processing ECG signals from a plurality of electrocardiogram ("ECG") leads connected to a patient, applying the ECG signals from the ECG leads to a low-pass filter to obtain a low-band filter ("LBF") energy values for the lead and to a high-pass filter ("HBF") to obtain high-band filter energy values for the leads. Running averages of LBF and HBF energy values are utilized to calculate signal-to-noise ("S/N") ratios for the leads. The S/N ratios are used to select two leads for providing ECG signals to an ECG signal processing algorithm.