Heart-sound analyzing apparatus

• US 20020035337A1
• Filed: 04/02/2001
• Published: 03/21/2002
• Est. Priority Date: 08/09/2000
• Status: Active Grant

• Current Assignee: Omron Healthcare Company Limited (Omron Corporation)
• Original Assignee: Colin Corporation (Fukuda Denshi Company Limited)
• Inventors: Oka, Tohru
• Granted Patent: US 6,626,842 B2
• Time in Patent Office: Days
• US Class Current: 600/528
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/0285 Measuring or recording phase velocity of blood waves
• CPC Class Codes: A61B 5/0295 using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
• CPC Class Codes: A61B 5/0809 by impedance pneumography
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61B 7/005 Detecting noise caused by implants, e.g. cardiac valves
• CPC Class Codes: A61B 7/04 Electric stethoscopes microphones, acoustic transducers therefor H04R

Abstract

A heart-sound analyzing apparatus, including a heart-sound microphone which is adapted to be worn on a living subject to iteratively detect a second heart sound II of the subject, a respiration-synchronous-signal detecting device which iteratively detects a respiration-synchronous signal of the subject, an inspiration-expiration judging device for judging, based on each of the respiration-synchronous signals iteratively detected by the respiration-synchronous-signal detecting device, whether the subject is in an inspiring state or in an expiring state, and an aortic-valve-closing-timing determining device for iteratively determining a timing when the aortic valve of the heart of the subject closes, based on each of second heart sounds II which are iteratively detected by the heart-sound microphone in time intervals, respectively, in each of which the subject is judged as being in the inspiring state by the inspiration-expiration judging device.

Claims

1. A heart-sound analyzing apparatus, comprising

a heart-sound microphone which is adapted to be worn on a living subject to iteratively detect a second heart sound II of the subject;

a respiration-synchronous-signal detecting device which iteratively detects a respiration-synchronous signal of the subject;

an inspiration-expiration judging means for judging, based on each of the respiration-synchronous signals iteratively detected by the respiration-synchronous-signal detecting device, whether the subject is in an inspiring state or in an expiring state; and

an aortic-valve-closing-timing determining means for iteratively determining a timing when an aortic valve of a heart of the subject closes, based on each of a plurality of second heart sounds II which are iteratively detected by the heart-sound microphone in a plurality of time intervals, respectively, in each of which the subject is judged as being in the inspiring state by the inspiration-expiration judging means.

2. An apparatus according to claim 1, wherein the aortic-valve-closing-timing determining means determines a timing when the aortic valve closes, based on a last one of a plurality of second heart sounds II which are detected by the heart-sound microphone in each of the plurality of time intervals in each of which the subject is judged as being in the inspiring state by the inspiration-expiration judging means.

3. An apparatus according to claim 1, further comprising:

a smoothing means for smoothing, by differentiation, a waveform of the second heart sounds iteratively detected by the heart-sound microphone; and

a squaring means for squaring respective amplitudes of a plurality of data points on the smoothed waveform that are determined with respect to a base line of the smoothed waveform,

wherein the aortic-valve-closing-timing determining means iteratively determines a timing when the aortic valve closes, based on the amplitudes squared by the squaring means.

4. An apparatus according to claim 1, further comprising an electrocardiograph which includes a plurality of electrodes adapted to be worn at a plurality of locations on the subject and which detects, through the electrodes, an electrocardiogram of the subject, wherein the aortic-valve-closing-timing determining means comprises means for iteratively determining, based on a prescribed point of each of respective first half portions of a plurality of T-waves of the electrocardiogram detected by the electrocardiograph, a start point of a corresponding one of a plurality of waveform-process intervals in each of which the aortic-valve-closing-timing determining means is to seek a timing when the aortic valve closes.

5. A system for obtaining information relating to a propagation velocity at which a pulse wave propagates along an artery of a living subject, the system comprising:

a heart-sound analyzing apparatus according to claim 1;

a pulse-wave detecting device which is adapted to be worn on the subject to detect the pulse wave which propagates along the artery of the subject; and

a pulse-wave-propagation-velocity-relating-information obtaining means for obtaining said information based on the timing when the aortic valve closes, determined by the aortic-valve-closing-timing determining means of the heart-sound analyzing apparatus, and a timing when a prescribed point of the pulse wave is detected by the pulse-wave detecting device.

6. A system according to claim 5, wherein the pulse-wave-propagation-velocity-relating-information obtaining means comprises a pulse-wave-propagation-time determining means for determining, based on the timing when the aortic valve closes, and the timing when the prescribed point of the pulse wave is detected by the pulse-wave detecting device, a propagation time needed for the pulse wave to propagate from the aortic valve to a position where the pulse-wave detecting device is worn on the subject.

7. A system according to claim 5, further comprising an output device which outputs the information obtained by the pulse-wave-propagation-velocity-relating-information obtaining means, so that an observer can see the output information.