ECG Signal SNR Enhancement via XASA Algorithm
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Solution Overview
Problem
Current cardiac devices face challenges in accurately detecting cardiac beats from surface or subcutaneous ECG signals due to noise interference and limited signal-to-noise ratio, and existing subcutaneous ECG monitors have design limitations that hinder effective implantation and signal sensing.
Innovation Solution
A method and device that enhance the signal-to-noise ratio of ECG signals using a Cross-check and Adjustment of Signal Amplitude (XASA) algorithm, which processes multiple input signals to generate composite signals with improved SNR, and a cardiac device with an asymmetric geometry and multiple sensing electrodes for enhanced signal sensing and implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If subcutaneous ECG monitoring is used to continuously record ECG signals, then the ability to capture infrequent arrhythmia episodes is improved, but the measurement noise from loose contact, muscle movement, and environmental factors increases
Solution Approach 1:
The patent divides the ECG signal into multiple segments and uses multiple sensing electrodes to capture signal components from different spatial locations. By segmenting the signal processing and using distributed sensing, the system can distinguish true cardiac signals from noise through comparative analysis of multiple signal segments and electrode readings.
Solution Approach 2:
The patent combines signals from multiple sensing electrodes and multiple ECG leads into a composite signal through signal processing algorithms. This merging of multiple signal sources enhances the signal-to-noise ratio by aggregating true signal components while averaging out random noise, thereby improving the reliability of arrhythmia detection.
2Duration of action of stationary object
If Holter recording with skin electrodes is used for continuous ECG monitoring, then the duration of monitoring is extended, but the ease of operation and patient comfort deteriorates
Solution Approach 1:
The patent extracts the ECG sensing function from the external Holter device and relocates it to an implantable subcutaneous pocket. By taking out the sensing electrodes from the external body surface and placing them in a subcutaneous location, the system eliminates the discomfort of skin electrodes while maintaining continuous monitoring capability.
Solution Approach 2:
The patent introduces a subcutaneous pocket as an intermediary structure that houses the sensing electrodes. This intermediary location provides a stable, comfortable environment for the electrodes while still allowing access to cardiac electrical signals, thereby mediating between the need for continuous monitoring and patient comfort.
3Device complexity
If existing ECG beat detection methods are used, then the device complexity is reduced, but the measurement precision of cardiac beat detection deteriorates
Solution Approach 1:
The patent adds a spatial dimension to ECG signal acquisition by using multiple sensing electrodes arranged in specific geometric patterns. This dimensional expansion from single-point to multi-point sensing enables more precise beat detection through analysis of signal morphology and timing across different spatial locations, improving precision without excessive complexity.
Solution Approach 2:
The patent changes the parameters of signal processing by using adaptive thresholds and dynamic filtering algorithms that adjust based on the characteristics of the input signal. These parameter changes enable the system to maintain high detection precision across varying physiological conditions while keeping the overall device complexity manageable through algorithmic optimization.
Data Source
AI summary
A method of enhancing the signal-to-noise ratio (SNR) of measured electrocardiogram (ECG) signals is provided. The method includes the steps of providing at least three cardiac input signals derived from the measured ECG signals S1 and forming a first estimate U1 S2 from each of at least three pairs of input signals. Moreover, the method includes the steps of forming a second estimate U2 S3 from each of at least three input signals; comparing S4 the polarity and the amplitude of a first and second estimate U1, U2 to at least one threshold T; generating S5 a composite signal X, wherein the polarity and the amplitude of the composite signal X depend on the result of the comparison; and using S6 the generated composite signal X to produce an output signal with enhanced signal-to-noise ratio (SNR). Furthermore, a corresponding cardiac device is also provided.