Medical instrument for noninvasive measurement of cardiovascular characteristics
First Claim
1. An apparatus for noninvasive quantitative measurement of characteristics of a cardiovascular system of a human object, the instrument comprising:
- noninvasive pulse transducer means for providing signal pulses representative of sensed heart beats of the human subject;
voluntary cardiorespiratory synchronization means responsive to the signal pulses for providing stimulae which permit the human subject to voluntarily synchronize the subject'"'"'s respiratory cycles with the subject'"'"'s heart beats;
instantaneous heart rate measurement means responsive to the signal pulses for providing digital data representative of instantaneous heart rate at each heart beat of a plurality of N-beat voluntarily synchronized respiratory cycles;
data sorting means for sorting the digital data by each of N-beat categories;
data analysis means for analyzing the sorted digital data to derive a digital value indicative of a characteristic of the subject'"'"'s cardiovascular system; and
output means for providing a human perceivable output as a function of the derived digital value.
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Abstract
A medical instrument includes a noninvasive pulse transducer which senses heart beats of a human subject. Based upon pulse signals from the transducer, the instrument provides visual stimulae which allow the human subject to voluntarily synchronize the subject'"'"'s respiration cycles with the subject'"'"'s heart beats. At the same time, the instrument determines and stores the instantaneous beat-to-beat heart rate for each beat of the respiratory cycles. After a predetermined number of synchronized respiratory cycles have been completed, the instrument performs both classical statistical and rhythmometric analyses utilizing the stored instantaneous heart rates. The instrument determines from these analyses mean and standard error values for each beat of the respiratory cycle; an analysis of variance of the mean value; a rhythm qualified mean heart rate value; an amplitude value; a timing value (which indicates the location of the peak of the cosine curve best fitting the heart rate data within the respiratory cycle), and a percent rhythm value (which indicates the quality of the fit with the cosine curve to the stored instantaneous heart rates). The amplitude value provides an indication of the physiological (as opposed to chronological) cardiovascular age of the human subject, since it indicates the compliance of the heart tissue. The effect of cardiotoxins, cardiac drugs, other substances, as well as altered physiologic states upon a subject'"'"'s heart tissue compliance also can be monitored using the amplitude, mean and peak timing values produced by the instrument. The instrument provides a displayed and/or printed output so that the subject or his or her physician has a simple yet accurate indication of heart condition which may be evaluated periodically and followed over time.
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Citations
35 Claims
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1. An apparatus for noninvasive quantitative measurement of characteristics of a cardiovascular system of a human object, the instrument comprising:
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noninvasive pulse transducer means for providing signal pulses representative of sensed heart beats of the human subject; voluntary cardiorespiratory synchronization means responsive to the signal pulses for providing stimulae which permit the human subject to voluntarily synchronize the subject'"'"'s respiratory cycles with the subject'"'"'s heart beats; instantaneous heart rate measurement means responsive to the signal pulses for providing digital data representative of instantaneous heart rate at each heart beat of a plurality of N-beat voluntarily synchronized respiratory cycles; data sorting means for sorting the digital data by each of N-beat categories; data analysis means for analyzing the sorted digital data to derive a digital value indicative of a characteristic of the subject'"'"'s cardiovascular system; and output means for providing a human perceivable output as a function of the derived digital value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. An apparatus for noninvasive quantitative measurement of characteristics of a cardiovascular system of a human subject, the apparatus comprising:
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noninvasive pulse transducer means for providing signal pulses representative of sensed heart beats of the human subject; voluntary cardiorespiratory synchronization means responsive to the signal pulses for providing stimulae which permit the human subject to voluntarily synchronize the subject'"'"'s respiratory cycles with the subject'"'"'s heart beats so that each respiratory cycle has a period corresponding to a predetermined number N of heart beats; instantaneous heart rate measurement means for providing digital data representative of instantaneous heart rate at each sensed heart beat based upon the signal pulses; means for storing the digital data for each sensed heart beat during a plurality of N-beat voluntarily synchronized respiratory cycles; statistical analysis means for deriving a plurality of digital statistical values based upon the digital data; rhythmometric analysis means for deriving a plurality of digital rhythm parameter values based upon the digital data; and means for providing an output signal based upon at least one digital value derived from the digital data. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A noninvasive method of measuring condition of the cardiovascular system of a human subject, the method comprising:
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providing a signal pulse in response to each sensed heart beat of the human subject; providing stimulae to the human subject, as a function of the signal pulses, which stimulae permit the human subject to voluntarily synchronize the subject'"'"'s respiratory cycles with the subject'"'"'s sensed heart beats, so that a first number N1 of heart beats occur during an inhalation portion of each N-beat respiratory cycle and a second number N2 of heart beats occur during an expiration portion of each N-beat respiratory cycle; determining, based upon time intervals between the signal pulses, instantaneous heart rates for each sensed heart beat during a plurality of voluntarily synchronized N-beat respiratory cycles; deriving a cosine curve which best characterizes the instantaneous heart rates during the voluntarily synchronized N-beat cycles; and providing an output signal based upon the derived cosine curve. - View Dependent Claims (31, 32, 33, 34, 35)
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Specification