Wearable Defibrillator ECG Signal Reliability Assessment
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Solution Overview
Problem
Wearable Cardioverter Defibrillators (WCDs) face challenges in obtaining accurate heart rate signals due to noise generated by patient movement at the electrode-skin interface, which can lead to missed cardiac episodes.
Innovation Solution
The WCD system employs multiple ECG sensing electrodes to generate multiple differential ECG vectors, using a reliability module to assess and classify ECG signals as reliable or unreliable by comparing heart rates determined through different methods, such as time domain and frequency domain analysis, and performs a rhythm analysis using only the reliable signals to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple ECG sensing electrodes are used to generate multiple differential ECG vectors, then the reliability of ECG signal assessment is improved, but the device complexity increases
Solution Approach 1:
The patent divides the ECG monitoring function into multiple independent sensing electrodes that generate separate differential ECG vectors. Each electrode pair creates an independent signal channel, allowing the system to segment the monitoring task across multiple sources. This segmentation enables the reliability module to independently assess each vector and select the most reliable signal, thereby improving overall assessment reliability while managing complexity through modular architecture.
2Measurement precision
If heart rate signals are analyzed using multiple methods (time domain and frequency domain), then the accuracy of rhythm analysis is improved, but the loss of time increases
Solution Approach 1:
The patent implements preliminary action by having the reliability module continuously monitor and pre-assess the quality of ECG signals from multiple vectors before rhythm analysis is performed. The system maintains a running assessment of signal reliability metrics, so when rhythm analysis is needed, the most reliable signal is already identified and ready for immediate processing. This preliminary assessment eliminates the need for time-consuming quality checks during critical rhythm analysis moments, thereby reducing time loss while maintaining high measurement precision.
3Measurement precision
If noise interference is reduced through multiple signal vectors, then the measurement precision of heart rate is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple differential ECG vectors into a unified assessment through the reliability module. The module combines information from multiple electrode pairs and their respective signal quality metrics to determine the most reliable signal source. By merging multiple noisy signals through intelligent selection and combination strategies, the system achieves superior noise reduction and measurement precision while managing complexity through algorithmic integration rather than hardware multiplication.
Data Source
AI summary
A method to determine reliable electrocardiogram (ECG) signal is described. The method includes receiving at least one ECG signal for a period of time from a patient. The method also includes analyzing the at least one ECG signal to determine a first heart rate using a first method and analyzing the at least one ECG signal to determine a second heart rate using a second method different from the first method. The method includes comparing the first and second heart rates to each other and classifying the at least one ECG signal as reliable when a reliability threshold is satisfied.