Implantable devices and methods using frequency-domain analysis of thoracic signal
First Claim
1. An apparatus comprising:
- an implantable housing, the implantable housing comprising;
a thoracic monitor circuit, including an output to provide time domain thoracic information;
a signal processor circuit, the signal processor circuit comprising;
a time-to-frequency domain converter circuit, including an input coupled to the thoracic monitor circuit output to receive the time domain thoracic information, and including an output providing frequency domain thoracic information; and
a spectrum analyzer circuit, including a input coupled to the time-to-frequency domain converter circuit output to receive the frequency domain thoracic information, and including an output to provide a classification of a pulmonary physiological state using a respiration component of the frequency-domain thoracic information, the classification of the pulmonary physiological state indicative of at least one of pulmonary obstructive disease, a restrictive respiration disease, rapid shallow non-periodic respiration, and respiration having decreased inhalation duration and increased exhalation duration.
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Abstract
This document describes, among other things, systems, devices, and methods that use frequency domain analysis of a thoracic signal. One example uses frequency domain analysis for discriminating between different pulmonary physiological states. Examples of breathing states include normal breathing, periodic breathing, Cheyne-Stokes breathing, obstructed respiration, restrictive respiration, and pulmonary edema. The frequency domain analysis may also be used for performing heart rate variability (HRV) diagnostics. In one example, a frequency domain adaptive filter implements a variable cutoff frequency for separating heart contraction spectral content and other spectral content from lower frequency respiration spectral content and other lower frequency spectral content.
86 Citations
56 Claims
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1. An apparatus comprising:
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an implantable housing, the implantable housing comprising; a thoracic monitor circuit, including an output to provide time domain thoracic information; a signal processor circuit, the signal processor circuit comprising; a time-to-frequency domain converter circuit, including an input coupled to the thoracic monitor circuit output to receive the time domain thoracic information, and including an output providing frequency domain thoracic information; and a spectrum analyzer circuit, including a input coupled to the time-to-frequency domain converter circuit output to receive the frequency domain thoracic information, and including an output to provide a classification of a pulmonary physiological state using a respiration component of the frequency-domain thoracic information, the classification of the pulmonary physiological state indicative of at least one of pulmonary obstructive disease, a restrictive respiration disease, rapid shallow non-periodic respiration, and respiration having decreased inhalation duration and increased exhalation duration. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An apparatus comprising:
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an implantable housing, the implantable housing comprising; a thoracic monitor circuit, including an output to provide time domain thoracic information; and a signal processor circuit, the signal processor circuit comprising; a time-to-frequency domain converter circuit, including an input coupled to the thoracic monitor circuit output to receive the time domain thoracic information, and including an output providing frequency domain thoracic information; and a frequency domain adaptive filter, the frequency domain adaptive filter including a first input coupled to the output of the time-to-frequency domain converter circuit, the frequency domain adaptive filter including a second input to receive a time domain heart rate signal, the frequency domain adaptive filter configured to distinguish a respiration component of the frequency domain thoracic information from a heart contraction component of the frequency domain thoracic information to provide a classification of a pulmonary physiological state using a respiration component of the frequency-domain thoracic information, the classification of the pulmonary physiological state indicative of at least one of pulmonary obstructive disease, a restrictive respiration disease, rapid shallow non-periodic respiration, and respiration having decreased inhalation duration and increased exhalation duration. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method comprising:
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detecting a time domain thoracic signal using an implanted device; transforming the time domain thoracic signal into a frequency-domain thoracic signal; filtering the frequency domain thoracic signal in the frequency domain to obtain frequency domain respiration information; and classifying a pulmonary physiological state to be indicative of at least one of pulmonary obstructive disease, a restrictive respiration disease, rapid shallow non-periodic respiration, and respiration having decreased inhalation duration and increased exhalation duration. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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43. A method comprising:
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detecting a time domain thoracic signal using an implanted device; detecting a heart rate; transforming the time domain thoracic signal into a frequency domain thoracic signal; and filtering the frequency domain thoracic signal in the frequency domain using a cutoff frequency that varies as a function of the detected heart rate; and classifying a pulmonary physiological state to be indicative of at least one of pulmonary obstructive disease, a restrictive respiration disease, rapid shallow non-periodic respiration, and respiration having decreased inhalation duration and increased exhalation duration. - View Dependent Claims (44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56)
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Specification