Electrocardiogram enhancement system and method
First Claim
1. A method for enhancing an electrocardiogram signal having frequency, low amplitude notches that are difficult to visually detect within an electrocardiogram signal waveform and that have frequencies above the signal recording bandwidth of a conventional chart recorder, said signal having a plurality of frequency components, each frequency component having a frequency, phase and amplitude, the frequencies of the frequency components comprising a first inter-component frequency relationship and the phases of the frequency components comprising a first inter-component phase relationship said enhancement method comprising the steps of:
- selectively amplifying frequency components representing the notches relative to other frequency components in the electrocardiogram signal; and
expanding said electrocardiogram signal including the amplified frequency components in time scale by a time scale expansion factor, frequency components representing said expanded signal having a second intercomponent frequency relationship and a second inter-component phase relationship equivalent to said first inter-component frequency relationship and first inter-component phase relationship, said expanded signal having a frequency range within the bandwidth of a conventional chart recorder.
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Accused Products
Abstract
An electrocardiogram enhancement system and apparatus is provided. Small amplitude, high frequency notches associated with myocardial disease and arrhythmias can be recorded by conventional chart recorders. In addition, the notches are clearly visible in the recorded waveform for visual detection and analysis of the notches by medical personnel.
In the system of the present invention electrocardiogram signals having small amplitude, high frequency notches are enhanced; first, by selectively amplifying the notches while keeping the amplitude of the remainder of the waveform constant and, second, by uniformly expanding the signal in the time domain wherein the inter-component frequency and inter-component phase relationships are maintained.
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Citations
52 Claims
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1. A method for enhancing an electrocardiogram signal having frequency, low amplitude notches that are difficult to visually detect within an electrocardiogram signal waveform and that have frequencies above the signal recording bandwidth of a conventional chart recorder, said signal having a plurality of frequency components, each frequency component having a frequency, phase and amplitude, the frequencies of the frequency components comprising a first inter-component frequency relationship and the phases of the frequency components comprising a first inter-component phase relationship said enhancement method comprising the steps of:
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selectively amplifying frequency components representing the notches relative to other frequency components in the electrocardiogram signal; and expanding said electrocardiogram signal including the amplified frequency components in time scale by a time scale expansion factor, frequency components representing said expanded signal having a second intercomponent frequency relationship and a second inter-component phase relationship equivalent to said first inter-component frequency relationship and first inter-component phase relationship, said expanded signal having a frequency range within the bandwidth of a conventional chart recorder. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for enhancing an electrocardiogram signal in a first frequency range having high frequency, low amplitude notches that are difficult to visually detect and analyze within an electrocardiogram signal waveform and that have frequencies above the signal recording bandwidth of a conventional chart recorder, said enhancement method comprising the steps of:
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performing a Fourier transform operation upon the electrocardiogram signal whereby a frequency spectrum signal is obtained, said frequency spectrum signal comprising frequency components having an amplitude, frequency, and phase, the frequencies of the frequency components comprising a first inter-component frequency relationship and the phases of the frequency components comprising a first inter-component phase relationship; selecting frequency components within a predetermined frequency range and greater than a minimum amplitude value that are indicative of notches; amplifying each of the selected frequency components by an amplification factor; expanding the frequency spectrum signal in time scale by dividing each frequency component by a time scale expansion factor, frequency components having a second inter-component frequency and second inter-component phase relationship equivalent to said first inter-component frequency and first inter-component phase relationship; and performing an inverse Fourier transform operation upon the expanded frequency spectrum signal to obtain an enhanced electrocardiogram signal, said enhanced electrocardiogram signal having a frequency range within the signal recording bandwidth of conventional chart recorders. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. Apparatus for enhancing an electrocardiogram signal having high frequency, low amplitude notches that are difficult to visually detect within an electrocardiogram signal waveform and that have frequencies above the signal recording bandwidth of a conventional chart recorder, said signal having a plurality of frequency components, each frequency component having a frequency, phase and amplitude, the frequencies of the frequency components comprising a first inter-component frequency relationship and the phases of the frequency components comprising a first inter-component phase relationship, said apparatus comprising:
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means for selectively amplifying frequency components representing the notches relative to other frequency components in the electrocardiogram signal; and means for expanding said electrocardiogram signal including the amplified frequency components in time scale by a time scale expansion factor, frequency components representing said expanded signal having a second inter-component frequency relationship and second inter-component phase relationship equivalent to said first inter-component frequency relationship and first inter-component phase relationship, said expanded signal being within the bandwidth of a conventional chart recorder, whereby the expanded signal is accurately recorded, and the high frequency, low amplitude notches are made visible - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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36. Apparatus for enhancing an electrocardiogram signal in a first frequency range having high frequency, low amplitude notches that are difficult to visually detect and analyze within a electrocardiogram signal waveform and that have frequencies above the signal recording bandwidth of a conventional chart recorder comprising:
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means for performing a Fourier transform operation upon the electrocardiogram signal whereby a frequency spectrum signal is obtained, said frequency spectrum signal comprising frequency components having an amplitude, frequency, and phase, the frequencies of the frequency components comprising a first inter-component frequency relationship and the phases of the frequency components comprising a first inter-component phase relationship; means for selecting frequency components within a predetermined frequency range and greater than a minimum amplitude value that are indicative of notches; means for amplifying each of the selected frequency components by an amplification factor; means for expanding the frequency spectrum in time scale by dividing each frequency component by a time scale expansion factor, frequency components having a second inter-component frequency relationship and a second inter-component phase relationship equivalent to said first inter-component frequency relationship and first inter-component phase relationship; means for performing an inverse Fourier transform operation upon the expanded frequency spectrum signal to obtain an enhanced electrocardiogram signal, said enhanced electrocardiogram signal having a frequency range within the bandwidth of conventional chart recorders; and chart recording means for display of the expanded signal where in the high frequency, low amplitude notches are visible within the displayed signal. - View Dependent Claims (37, 38, 39, 40, 41, 42, 43)
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44. A method for enhancing an electrocardiogram signal having high frequency, low amplitude notches that have frequencies above 100 Hz and are difficult to visually detect within an electrocardiogram signal waveform, said signal having a plurality of frequency components, each frequency component having a frequency, phase and amplitude, said enhancement method comprising the steps of:
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amplifying the frequency components above 100 Hz relative to other frequency components in the electrocardiogram signal by an amplification factor; and
thenexpanding said electrocardiogram signal including the amplified frequency components in time scale by a time scale expansion factor to produce an expanded signal, said expanded signal having frequency components in which the frequencies are those of the frequency components of the electrocardiogram signal divided by the time scale expansion factor, said expanded signal having a frequency range within the bandwidth of a conventional chart recorder. - View Dependent Claims (45, 46, 47)
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48. Apparatus for enhancing an electrocardiogram signal having high frequency, low amplitude notches that have frequencies above 100 Hz and are above the signal recording bandwidth of a conventional chart recorder and difficult to visually detect within an electrocardiogram signal waveform, said signal being within a first frequency range and having a plurality of frequency components, each frequency component having a frequency, phase and amplitude, said apparatus comprising:
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means for amplifying the frequency components above 100 Hz relative to other frequency components in the electrocardiogram signal by an amplification factor; and means for expanding said electrocardiogram signal including the amplified frequency components in time scale by a time scale expansion factor to produce an expanded signal, said expanded signal having frequency components in which the frequencies are those of the frequency components of the electrocardiogram signal divided by the time scale expansion factor, said expanded signal having a frequency range within the bandwidth of a conventional chart recorder. - View Dependent Claims (49, 50, 51, 52)
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Specification