Multi-Resolution Signal Processing for Cardiac Arrhythmia Detection

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Solution Overview

Problem

Current methods for detecting atrial fibrillation (AF) often miss asymptomatic episodes, which can lead to continued stroke risk and atrial remodeling, as they rely on event-based analysis that is not sensitive enough to detect morphological changes in cardiac signals.

Innovation Solution

A multi-resolution signal-processing framework that combines digital signal processing with event-based algorithms, using wavelet multi-resolution analysis to identify key morphological features in electrograms, generating characterization vectors that an inference engine uses to determine the presence of AF.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If event-based analysis algorithms are used to detect cardiac arrhythmia, then the detection process is simple and based on binary events, but the sensitivity to detect morphological changes and asymptomatic AF is insufficient

Engineering Contradiction:
Improvedetection sensitivityVSAvoidanalysis algorithm complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the ECG signal into multiple resolution levels using wavelet transform, allowing analysis of morphological features at different scales. This segmentation enables detection of subtle asymptomatic AF patterns that would be missed in conventional binary event-based analysis while maintaining computational efficiency through hierarchical processing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension of analysis by transforming the one-dimensional ECG signal into multi-resolution wavelet coefficients. This dimensional transformation enables morphological analysis across different time-scales, providing the ability to detect subtle pattern changes that conventional single-resolution methods cannot identify.

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

2Reliability

If morphological analysis of EGM is performed using digital signal processing, then detection of asymptomatic AF is improved, but the computational complexity and processing requirements increase

Engineering Contradiction:
ImproveAF detection accuracyVSAvoidsignal processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The wavelet transform decomposes the complex ECG signal into separate frequency bands and time-scale components, allowing morphological analysis to focus on specific resolution levels. This segmentation reduces computational complexity by enabling targeted analysis of relevant frequency components rather than processing the entire signal at full resolution.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different analysis qualities to different regions of the ECG signal through multi-resolution wavelet analysis. By allowing variable resolution at different time-scales and locations, the system can concentrate computational resources on segments with abnormal morphology while using simpler processing for normal segments, improving overall efficiency.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS7412282B2Algorithms for detecting cardiac arrhythmia and methods and apparatuses utilizing the algorithms
Publication Date: 2008.08.12 MEDTRONIC INC
  • US7412282B2 patent drawing
  • US7412282B2 patent drawing
  • US7412282B2 patent drawing

AI summary

A method for detecting a cardiac arrhythmia from an electrocardiogram includes the steps of identifying a plurality of R-waves in the electrocardiogram during a predetermined time interval; extracting heartbeat complexes corresponding to the identified R-waves; identifying a key region within each heartbeat complex that is morphologically altered in the event of the cardiac arrhythmia; calculating a statistical measurement of an ensemble of the key regions from each of the heartbeat complexes; and determining from the statistical measurement whether the cardiac arrhythmia occurred during the predetermined time interval. An apparatus is also provided that includes a processor that is coupled to receive an electrocardiogram, and is configured in response thereof to perform the method for detecting a cardiac arrhythmia.