Surgery – Diagnostic testing – Cardiovascular
Reexamination Certificate
1999-12-09
2001-07-31
Getzow, Scott (Department: 3762)
Surgery
Diagnostic testing
Cardiovascular
Reexamination Certificate
active
06269263
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of The Invention
The present invention relates to a method for estimating a heart rate variability and an apparatus for embodying such estimation, and more particularly to a method for estimating a heart rate variability and an apparatus for embodying such estimation which can be operated at a low sampling frequency and by which a heart rate variability (HRV) can be easily estimated from electrocardiogram data.
2. Description of The Related Art
In the field of medical procedure, HRV has been utilized heretofore in a diagnosis for heart diseases and the like. In this respect, a variety of manners for estimating an HRV from electrocardiogram data have been proposed.
As a conventional manner for estimating an HRV from electrocardiogram data, for example, a manner for estimating an HRV wherein peaks R on a waveform are detected from electrocardiogram data as shown in
FIG. 1
, and an inverse number of a time interval between peaks R is multiplied by 60 for estimating the number of beat in heart beats per minute has been known.
More specifically, in the above described manner, when it is assumed that a time instant when a peak R appears is represented by t
i
(i=0, 1, . . . , n), an HRV is determined by vectors [60/(t
1
−t
0
, 60/(t
2
−t
1
), . . . , 60/(t
n
−t
n−1
)]
t
.
Accordingly, peaks R on a waveform must be detected correctly from electrocardiogram data in the above described conventional manner, so that such a problem that a sampling frequency for detecting peaks R on a waveform becomes high in the case where an apparatus for estimating an HRV is constituted by utilizing a conventional manner, resulting in a complicated structure of the apparatus, besides it results in a high cost has been pointed out.
OBJECTS AND SUMMARY OF THE INVENTION
The present invention has been made in view of a problem involved in the prior art as described above, and an object of the invention is to provide a method for estimating a heart rate variability and the apparatus for embodying such estimation which can be operated at a low sampling frequency without detecting peaks on a waveform in electrocardiogram data.
In order to achieve the above described object, a method for estimating a heart rate variability from electrocardiogram data according to the present invention is constituted in such that frequencies in each of which a spectrum is maximum at a predetermined time are detected from the electrocardiogram data, and a heart rate variability is estimated on the basis of results obtained by filtering the electrocardiogram data with a band pass filter including the frequency detected as its center frequency.
Accordingly, there is no need of detecting peaks on a waveform in electrocardiogram data in accordance with a method for estimating a heart rate variability of the present invention.
Furthermore, a method for estimating a heart rate variability from electrocardiogram data according to the present invention is constituted in such that frequencies in each of which a spectrum is maximum at a predetermined time are detected from the electrocardiogram data, and a heart rate variability is estimated from a value acquired by multiplying an instantaneous angular frequency determined with use of Hilbert transform by a constant (60/2 &pgr;) on the basis of results obtained by filtering the electrocardiogram data with a band pass filter including the frequency detected as its center frequency.
Accordingly, there is no need of detecting peaks on a waveform in electrocardiogram data in accordance with a method for estimating a heart rate variability of the present invention.
With respect to the above description, when frequencies in each of which a spectrum is maximum at a predetermined time are detected from the electrocardiogram data, the detection may be conducted within a predetermined variable range.
Moreover, an apparatus for estimating a heart rate variability from electrocardiogram data according to the present invention comprises a detection means for detecting from electrocardiogram data frequencies in each of which a spectrum is maximum at a predetermined time, and a band pass filter including the frequency detected by the detection means as its center frequency, wherein a heart rate variability is estimated on the basis of results obtained by filtering the electrocardiogram data with the band pass filter.
Accordingly, there is no need of detecting peaks on a waveform in electrocardiogram data in accordance with an apparatus for estimating a heart rate variability of the present invention.
Furthermore, an apparatus for estimating a heart rate variability from electrocardiogram data according to the present invention comprises a detection means for detecting from electrocardiogram data frequencies in each of which a spectrum is maximum at a predetermined time, a band pass filter including a frequency detected by the detection means as its center frequency, and an instantaneous angular frequency acquiring means for determining an instantaneous angular frequency with the use of Hilbert transform from results obtained by filtering the electrocardiogram data by means of the band pass filter, and a multiplying means for multiplying the instantaneous angular frequency determined by the instantaneous angular frequency acquiring means by a constant (60/2 &pgr;), wherein a value produced from multiplication of the instantaneous angular frequency, determined by the instantaneous angular frequency acquiring means with the use of Hilbert transform from the results obtained by, filtering the electrocardiogram data by means of the band pass filter, by the constant (60/2 &pgr;) is estimated as a heart rate variability.
Accordingly, there is no need of detecting peaks on a waveform in electrocardiogram data in accordance with an apparatus for estimating a heart rate variability of the present invention.
With respect to the above description, when frequencies in each of which a spectrum is maximum at a predetermined time are detected from the electrocardiogram data, the detection means may detect a predetermined variable range.
REFERENCES:
patent: 5291400 (1994-03-01), Gilham
patent: 5423325 (1995-06-01), Burton
“Straight-Tempo: A Universal Tool to Manipulate Linguistic and Para-Linguistic Speech Information”, ATR HIP Res. Labs., 1997 vol. 2 of 2 by Hideki Kawahara.
Barros Allan Kardec
Ohnishi Noboru
Birch & Stewart Kolasch & Birch, LLP
Getzow Scott
Riken
LandOfFree
Method for estimating heart rate variability and apparatus... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for estimating heart rate variability and apparatus..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for estimating heart rate variability and apparatus... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2503129