System for adaptive filtering of cardiac signals
Inventors
Matthiesen, Mads Emil • Larsen, Sigge Nejst
Assignees
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Publication Number
US-11324453-B2
Publication Date
2022-05-10
Expiration Date
Abstract
System for filtering cardiac signals. The system includes: cardiac terminals (10a-d) adapted to collect cardiac electrophysiological potentials from a plurality of cardiac electrodes (1a-d) placed at respective cardiac locations in or on an individual (99) and a processor device (40) adapted to process one or more input signals, which are based on the collected electrophysiological potential(s). The processing includes running an adaptive filter algorithm on one or more signals based on the input signals. The adaptive filter algorithm is arranged to calculate estimated noise component(s) of the signals and arranged to subtract the estimated noise component(s) from the signals. In this way a cardiac signal is derived where the noise has been significantly reduced.
Core Innovation
The invention relates to a system for filtering cardiac signals using a processor device running an adaptive filter algorithm. The system collects cardiac electrophysiological potentials via a plurality of cardiac terminals and one or more indifferent electrophysiological potentials via one or more indifferent terminals, and an amplifier stage amplifies the collected potentials with respect to a signal reference to obtain respective cardiac and indifferent signals.
The processor processes a plurality of input signals based on the cardiac signal(s) and the indifferent signal(s), and runs an adaptive filter algorithm on one or more intermediate signals based on the plurality of input signals. The adaptive filter algorithm calculates one or more estimated noise component(s) of the intermediate signals and subtracts the estimated noise component(s) respectively from the intermediate signals to generate a filtered output signal.
The processing includes calculating an average of more than one of the input signals including the indifferent signal as well as the cardiac signals, or calculating an average of more than one signal based on the one or more cardiac signal(s). The calculated average is used by the adaptive filter algorithm to provide a first estimate of the frequency of the noise component with reduced common mode effects and reduced signal noise relative to the electro-physiological potentials.
Claims Coverage
The document includes two independent claims. Both center on adaptive filtering of intermediate cardiac signals by estimating noise component(s) and subtracting the estimated noise, and both use an average of multiple input or cardiac signals to obtain a first estimate of the noise component frequency, with the first independent claim further explicitly including indifferent electrodes and common-mode reduction.
Filtering cardiac signals with cardiac and indifferent terminals
A plurality of cardiac terminals adapted to collect cardiac electrophysiological potentials from a plurality of cardiac electrodes, and one or more indifferent terminal(s) adapted to collect one or more indifferent electrophysiological potentials from one or more indifferent electrodes, with an amplifier stage amplifying the cardiac and indifferent potentials with respect to a signal reference to obtain respective cardiac and indifferent signals.
Adaptive noise-component estimation and subtraction on intermediate signals
Running an adaptive filter algorithm on one or more intermediate signals based on the plurality of input signals, wherein the adaptive filter algorithm calculates one or more estimated noise component(s) of the one or more intermediate signals and subtracts the one or more estimated noise component(s) respectively from the one or more intermediate signals to generate a filtered output signal.
Averaging multiple input signals including indifferent signal for reduced common mode effects
Calculating an average of more than one of the plurality of input signals including the indifferent signal as well as the cardiac signals, and using the calculated average by the adaptive filter algorithm to provide a first estimate of the frequency of the noise component with reduced common mode effects and reduced signal noise relative to the electro-physiological potentials.
Adaptive filtering using cardiac signals and averaged cardiac signals
Running an adaptive filter algorithm on one or more intermediate signals based on input signals based on the cardiac signals, calculating one or more estimated noise component(s) of the intermediate signals, and subtracting the estimated noise component(s) respectively from the intermediate signals.
Averaging multiple cardiac signals for first estimate of noise frequency
Calculating an average of more than one signal based on the one or more cardiac signal(s), and using the calculated average by the adaptive filter algorithm to provide a first estimate of the frequency of the noise component.
Across both independent claims, the core claim coverage is an adaptive filter algorithm that estimates noise component(s) in intermediate signals and subtracts the estimated noise to generate filtered cardiac signal output, with the noise frequency estimate grounded in an average computed from multiple signals. The first independent claim further includes indifferent terminals and specifies that the average-based frequency estimate provides reduced common mode effects and reduced signal noise.
Stated Advantages
Provides a first estimate of the frequency of the noise component with reduced common mode effects.
Provides reduced signal noise relative to the electro-physiological potentials.
Documented Applications
Adaptive cardiac signal filtering for reducing mains interference in cardiac electrophysiological potentials acquired from in or on an individual using cardiac electrodes and indifferent electrodes [procedural detail omitted for safety].
Frequency spectrum analysis to determine which frequency or frequencies contribute most to noise in the context of the adaptive cardiac signal filtering system.
Spike detection to pause or stop adaptive filtering during cardiac signal artefacts in the cardiac signal filtering system.
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