Partial State Space Reconstruction for ECG Arrhythmia Detection

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Solution Overview

Problem

Traditional automated ECG signal analysis tools rely on correlation-based template matching and empirical decision rules, which are not optimal for all ECG databases, and often require multiple leads, leading to inefficiencies in data storage and monitoring applications, while also being prone to false positives and negatives in arrhythmia detection.

Innovation Solution

The use of partial state space reconstruction techniques, specifically the Hilbert transform, to generate a transformed signal that is mathematically orthogonal to the physiological signal, allowing for improved representation and analysis of heart dynamics in a lower dimensional space, enabling more accurate and automated detection of heart arrhythmias even with fewer leads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional correlation-based template matching and empirical decision rules are used for ECG analysis, then the system can identify heart beats using conventional methods, but the system suffers from false positives and negatives in arrhythmia detection and requires multiple leads leading to inefficiencies in data storage

Engineering Contradiction:
Improvearrhythmia detection accuracyVSAvoidnumber of leads required
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies state space reconstruction to transform the ECG signal from conventional time-series representation into a higher dimensional phase space. This dimensional transformation allows the system to capture dynamical features of heart beats more effectively, improving arrhythmia detection accuracy while enabling the use of fewer leads. The state space embedding creates a more discriminative representation where arrhythmic beats can be reliably distinguished from normal beats.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the representation parameters of the ECG signal by using state space coordinates instead of conventional time-domain features. This parameter transformation allows extraction of dynamical properties that are invariant to lead configuration, reducing the number of leads required while maintaining or improving detection reliability. The state space parameters capture the essential dynamics of cardiac electrical activity more efficiently.

Inventive Principle:
Principle #35Parameter changes

2Loss of information

If multiple leads are used in cardiac monitoring systems, then more comprehensive cardiac data can be obtained, but data storage requirements increase and monitoring application efficiency decreases

Engineering Contradiction:
Improvecardiac signal information completenessVSAvoiddata storage requirements
Core Design Contradiction:
Loss of informationVSQuantity of substance

Solution Approach 1:

The patent extracts the essential dynamical information from ECG signals by transforming them into state space representation. This extraction process identifies and isolates the key dynamical features that characterize cardiac activity, allowing the system to obtain comprehensive cardiac information from fewer leads. The state space transformation efficiently captures the essential dynamics without requiring redundant data from multiple leads, thereby reducing storage requirements while maintaining information completeness.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If conventional time series representation is used for heart beat classification, then the system can process ECG signals using traditional methods, but the classification accuracy for distinguishing ventricular beats from normal beats is limited

Engineering Contradiction:
Improveheart beat classification accuracyVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transforms the ECG signal from conventional time-series representation into a higher dimensional state space, where heart beats can be more effectively classified. This dimensional transformation creates a representation in which ventricular beats and normal beats are more distinctly separated, improving classification accuracy. The state space coordinates provide a more discriminative feature set for automated classification algorithms.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The state space representation serves multiple functions simultaneously: it captures dynamical features for classification, provides noise robustness, and enables automated distinction between different beat types. This universal representation approach improves classification accuracy while the automated nature of state space techniques actually reduces processing complexity compared to manual feature engineering in time domain.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS7996075B2Monitoring physiological activity using partial state space reconstruction
Publication Date: 2011.08.09 BRAEMAR MANUFACTURING LLC
  • US7996075B2 patent drawing
  • US7996075B2 patent drawing
  • US7996075B2 patent drawing

AI summary

Systems and techniques relating to monitoring physiological activity using partial state space reconstruction. In general, in one aspect, a partial state space is produced using an orthogonal, frequency-independent transform, such as Hilbert transform. The partial state space can then be analyzed using state space techniques to identify physiological information for the biological system. The described techniques can be implemented in a distributed cardiac activity monitoring system, including a cardiac monitoring apparatus, and a QRS detector thereof.