Surface ECG frequency analysis system and method based upon spectral turbulence estimation
First Claim
1. A method for detecting abnormalities of heart having a time varying QRS signal, said method comprising the steps ofpartitioning said QRS signal into a sequence of time displaced time segments,transforming said time segments into respective sets of spectral components, andcorrelating said sets of spectral components across the QRS signal, andgenerating an abnormality score when the correlation of said correlating step is above a predetermined state.
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Abstract
Frequency domain ECG signal processing systems and methods plot spectral maps and compute statistical parameters from surface electrocardiographic signals, which plots and parameters reveal abnormalities of electrical conduction within the hearts of patients at risk of ventricular tachycardia. Fourier analysis of short overlapping time segments of QRS ECG signal are used to create three dimensional spectral maps disclosing changes in the frequency spectral content of the ECG signal over the whole QRS region. Correlations and statistical evaluations of the spectral content between QRS time segment pairs quantify the spectral turbulence of the ECG and distinguish those at risk from ventricular tachyarrhythmias.
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Citations
35 Claims
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1. A method for detecting abnormalities of heart having a time varying QRS signal, said method comprising the steps of
partitioning said QRS signal into a sequence of time displaced time segments, transforming said time segments into respective sets of spectral components, and correlating said sets of spectral components across the QRS signal, and generating an abnormality score when the correlation of said correlating step is above a predetermined state.
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12. A method for detecting abnormalities of heart having a time varying QRS signal, said method comprising the steps of
signal averaging an ECG signal identifying the QRS signal of said ECG signal, differentiating said QRS signal dividing said differentiated QRS signal into a sequence of overlapping time segments, dividing each of said time segment into data points, multiplying data points of each of said time segments by a window function to weight each time segment, performing a discrete fast Fourier transform on each said windowed time segments, in which the power spectral density of a series of frequency components are calculated, and producing a numerical matrix or table ofpower spectral densities are located by frequency components and time segments, correlating said power spectral densities of said frequency components with each other across the QRS signal, computing an spectral turbulence parameters based upon the correlation of said power spectral densities, assigning an abnormality state in the presence of abnormal spectral turbulence.
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17. A method for detecting abnormalities of heart having a time varying QRS signal, said method comprising the steps of
signal averaging an ECG signal identifying the QRS signal of said ECG signal, differentiating said QRS signal dividing said differentiated QRS signal into a sequence of overlapping time segments, multiplying each said time segment by a window function to weight each time segment, performing a discrete fast Fourier transform on each said windowed time segments, in which the power spectral density of a series of frequency components are calculated, producing a numerical matrix or table ofpower spectral densities are located by frequency components and time segments, correlating said power spectral densities of said frequency components with each other across the QRS signal, computing an spectral turbulence parameters based upon the correlation of said power spectral densities, assigning an abnormality state in the presence of abnormal spectral turbulence.
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22. A system for detecting heart conditions comprising
first means for receiving said a QRS signal, and second means for generating an abnormality indicator, said second means connected to said first means, for dividing said QRS signal into a sequence of overlapping time segments each have a plurality of data points, for transforming said data points of each of said time segments into a matrix ofpower content indicators organized by time segment and frequency components, for correlating said power content indicators of said frequency components with said correlation upon successive time segments, for generating at least one spectral turbulence parameter based upon the correlation of successive time segments with said abnormality indicator based upon the value of said at least one spectral turbulence parameter.
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28. A system for detecting heart conditions comprising
first means for storing a sequence of QRS signals from a human heart, second means for receiving said QRS signals form said first means, third means for generating at least one abnormality indication, said third means connected to said second means, said third means for signal averaging said QRS signals, for dividing said signal averaged QRS signal into a sequence of overlapping time segments each have a plurality of data points, for transforming said data points of each of said time segments into a matrix ofpower content indicators organized by time segment and frequency components, for correlating said power content indicators of said frequency components with said correlation upon successive time segments, for generating at least one spectral turbulence parameter based upon the correlation of successive time segments with said at least one abnormality indication based upon the value of said at least one spectral turbulence parameter.
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29. A system for detecting heart conditions comprising
first means for receiving at least one QRS signal, second means for generating at least one abnormality indication, said second means connected to said first means, said second for dividing said at least one QRS signal into a sequence of overlapping time segments each have a plurality of data points, for transforming said data points of each of said time segments into a matrix ofpower content indicators organized by time segment and frequency components, for correlating said power content indicators of said frequency components with said correlation upon successive time segments, for generating at least one spectral turbulence parameter based upon the correlation of successive time segments with said at least one abnormality indication based upon the value of said at least one spectral turbulence parameter, and third means for displaying said at least one abnormality indicator.
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30. A system for detecting heart conditions comprising
a scanner adapted to receive Holter tapes storing a sequence of QRS signals, said scanner for scanning said tapes at high speed, a digital to analog converter for converting said QRS signal into digital type signal suitable for storing in a digital computer having memory, digital computer for generating at least one abnormality indication, said digital computer connected to a memory storing said converted QRS signal, said digital computer for dividing said at least one QRS signal into a sequence of overlapping time segments each have a plurality of data points, for transforming said data points of each of said time segments into a matrix ofpower content indicators organized by time segment and frequency components, for correlating said power content indicators of said frequency components with said correlation upon successive time segments, for generating at least one spectral turbulence parameter based upon the correlation of successive time segments with said at least one abnormality indication based upon the value of said at least one spectral turbulence parameter.
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35. An apparatus for providing an indicator of electrical heart conduction, said apparatus comprising
means for receiving QRS signal from a human being, electronic filters for isolating frequency components of said QRS signal, comparators for comparing isolated frequency components at intervals over said QRS signal, and electronic circuit connected to comparators for generating an indication of spectral turbulence.
Specification