Atrial Fibrillation Classification via Dominant Frequency Window

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Solution Overview

Problem

Current methods for classifying atrial fibrillation using ECG data are not robust, as they rely on finding a single dominant frequency, which inadequately describes the complex and chaotic nature of atrial fibrillation, leading to suboptimal treatment strategies and outcome predictions.

Innovation Solution

The method involves decomposing ECG data into frequency and amplitude dimensions to identify a dominant window containing a predefined percentage of signal power, rather than focusing on a single frequency, allowing for a more robust classification of atrial fibrillation complexity and severity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a single dominant frequency is identified from the ECG spectrum, then the classification method is simple to implement, but the classification accuracy and robustness deteriorate due to the chaotic nature of atrial fibrillation

Engineering Contradiction:
Improvesimplicity of classification methodVSAvoidclassification accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent segments the frequency spectrum into multiple frequency bands instead of identifying a single dominant frequency. Each frequency band is analyzed separately to determine its contribution to the atrial fibrillation signal, allowing for a more comprehensive and accurate classification that captures the chaotic multi-frequency nature of AF.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a one-dimensional approach (single frequency) to a two-dimensional approach by introducing both frequency and amplitude dimensions. The amplitude criterion based on sum of amplitudes adds a new dimension for evaluating frequency components, enabling more robust classification that accounts for the complex spectral distribution of atrial fibrillation.

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

2Device complexity

If the classification focuses on a single peak frequency, then the computational complexity is low, but the reliability of classification deteriorates due to random and temporary peaks in less relevant frequencies

Engineering Contradiction:
Improvecomputational complexityVSAvoidclassification robustness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent merges multiple frequency components that meet the amplitude criterion into a unified classification result. Instead of relying on a single peak frequency that may be spurious, the method combines evidence from multiple frequency bands, each contributing to the overall classification decision, thereby improving reliability through aggregation of multiple indicators.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements a feedback mechanism where the amplitude criterion is evaluated iteratively across different frequency bands. The classification process continuously refines its assessment by comparing the sum of amplitudes against the criterion, allowing the system to adjust and confirm classifications based on cumulative evidence from multiple frequency components rather than a single measurement.

Inventive Principle:
Principle #23Feedback

3Reliability

If a dominant window containing multiple frequencies is used instead of a single frequency, then the classification robustness improves, but the complexity of the analysis method increases

Engineering Contradiction:
Improveclassification robustnessVSAvoidanalysis method complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the evaluation parameter from single-frequency amplitude to sum of amplitudes across multiple frequencies within a dominant window. This parameter transformation allows the method to capture the distributed energy characteristic of atrial fibrillation while maintaining a clear decision criterion. The amplitude criterion based on summed amplitudes provides a straightforward metric that improves robustness without requiring excessively complex analysis.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4008254B1Method for classifying atrial fibrillation
Publication Date: 2023.10.04 CATHVISION APS
  • EP4008254B1 patent drawingFigure 1
  • EP4008254B1 patent drawingFigure 2

AI summary

The invention relates to a method for classifying atrial fibrillation by analysing ECG data (1) via a control system (2), wherein in a decomposition step the control system (2) decomposes the ECG data (1) by a frequency decomposition thereby generating frequency data (7), in particular a frequency spectrum, comprising a frequency dimension (f) and an amplitude dimension (a). It is proposed that in an analysis step the control system (2) identifies in the frequency data (7) a dominant window (8) having a width (9) in the frequency dimension (f) and meeting an amplitude criterion, that the amplitude criterion is based on a sum of amplitudes inside the dominant window (8), that the control system (2) identifies the dominant window (8) by searching on at least a section, in particular a pre-defined section, of the frequency dimension (f) for a window fulfilling the amplitude criterion and that based on the dominant window (8) the control system (2) determines the classification of atrial fibrillation in the ECG data (1).