US4802491A
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Method and apparatus for assessing myocardial electrical stability
Assignee: Massachusetts Institute of Technology
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Filing: 1986-07-30
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Granted: 1989-02-07
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Expires: 2006-07-30
Abstract
Abstract Myocardial electrical stability is assessed based on the derivation of an alternating ECG morphology index from a series of heartbeats. The ECG electrical signal waveform is digitized at a plurlaity of sample points for each of the series of beats. Sample point matrices from the digitized ECG signals are constructed and the alternating energy at each of the sample points for the series of beats is computed. The alternating energy over the entire set of sample points is summed to generate the total alternating energy. This total alternating energy is normalized with respect to the energy of the average waveform, the normalized value being the alternating ECG morphology index. Animal studies indicate a high negative correlation between cardiac electrical stability and the alternating ECG morphology index.
Inventors
- 👤 Richard J. Cohen
- 👤 Joseph M. Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:16
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/24; A61B5/316; A61B5/318; A61B5/346; A61B5/349; A61B5/35; A61B5/333; A61B5/336
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
60 words
Method for analyzing cycle-to-cycle variability in a physiologic waveform for assessing relative physiologic stability, comprising: digitizing the waveform at a plurality of sample points for each cycle; constructing two-dimensional sample point matrices, having rows and columns, from the digitized waveform; and analyzing variability in each column of the sample point matrices to form an index correlating with the physiologic stability.
Claim 2
Dependent Claim
60 words
Method for analyzing cycle-to-cycle variability in a physiologic waveform for assessing relative physiologic stability, comprising: digitizing the waveform at a plurality of sample points for each cycle; constructing two-dimensional sample point matrices, having rows and columns, from the digitized waveform; and analyzing variability in each column of the sample point matrices to form an index correlating with the physiologic stability.
Claim 3
Dependent Claim
13 words
The method of claim 1 further including analyzing the variability by spectral analysis.
Claim 4
Dependent Claim
15 words
The method of claim 1 further including analyzing the variability by time series domain analysis.
Claim 5
Dependent Claim
65 words
Apparatus for analyzing cycle-to-cycle variability in a physiologic waveform for assessing relative physiologic stability, comprising: means for digitizing the waveform at a plurality of sample points for each cycle; means for constructing sample point matrices, having rows and columns, from the digitized waveform; and means for analyzing variability in each column of the sample point matrices to form an index correlating with the physiologic stability.
Claim 6
Dependent Claim
65 words
Apparatus for analyzing cycle-to-cycle variability in a physiologic waveform for assessing relative physiologic stability, comprising: means for digitizing the waveform at a plurality of sample points for each cycle; means for constructing sample point matrices, having rows and columns, from the digitized waveform; and means for analyzing variability in each column of the sample point matrices to form an index correlating with the physiologic stability.
Claim 7
Dependent Claim
113 words
Method for deriving an alternating ECG morphology index from a series of heartbeats for assessing relative myocardial electrical stability, comprising: digitizing the ECG electrical signal waveform at a plurality of sample points for each of the beats; constructing sample point matrices, having rows and columns, from the digital ECG signal; computing the alternating energy at each of the sample points for the series of beats; summing the alternating energy over the entire set of sample points to generate a total alternating energy; and normalizing the total alternating energy with respect to energy of the average waveform, the normalized value being the alternating ECG morphology index, the index correlating with the myocardial electrical stability.
Claim 8
Dependent Claim
113 words
Method for deriving an alternating ECG morphology index from a series of heartbeats for assessing relative myocardial electrical stability, comprising: digitizing the ECG electrical signal waveform at a plurality of sample points for each of the beats; constructing sample point matrices, having rows and columns, from the digital ECG signal; computing the alternating energy at each of the sample points for the series of beats; summing the alternating energy over the entire set of sample points to generate a total alternating energy; and normalizing the total alternating energy with respect to energy of the average waveform, the normalized value being the alternating ECG morphology index, the index correlating with the myocardial electrical stability.
Claim 9
Dependent Claim
39 words
The method of claim 5 further including calculating a spectral noise estimate at a frequency band below the freqeuncy of the alternating energy and comparing the summation with the spectral noise estimate, the comparison being a test for significance.
Claim 10
Dependent Claim
16 words
The method of claim 5 further including estimating fiducial points for each of the beat signals.
Claim 11
Dependent Claim
20 words
The method of claim 5 further including low pass filtering the ECG electrical signals before digitizing the ECG signal waveform.
Claim 12
Dependent Claim
21 words
The method of claim 5 wherein the ECG signals are digitized by sampling at a rate of 1,000 samples per second.
Claim 13
Dependent Claim
122 words
Method for assessing relative myocardial electrical stability comprising determining the alternating ECG morphology index comprising: digitizing the ECG electrical signal waveform at a plurality of sample points for each of the beats; constructing sample point matrices, having rows and columns, from the digital ECG signal; computing the alternating energy at each of the sample points for the series of beats; summing the alternating energy over the entire set of sample points to generate a total alternating energy; normalizing the total alternating energy with respect to energy of the average waveform, the normalized value being the alternating ECG morphology index; and monitoring the changes in the alternating ECG morphology index; increases in this index correlating with lower myocardial electrical stability and vice versa.
Claim 14
Dependent Claim
122 words
Method for assessing relative myocardial electrical stability comprising determining the alternating ECG morphology index comprising: digitizing the ECG electrical signal waveform at a plurality of sample points for each of the beats; constructing sample point matrices, having rows and columns, from the digital ECG signal; computing the alternating energy at each of the sample points for the series of beats; summing the alternating energy over the entire set of sample points to generate a total alternating energy; normalizing the total alternating energy with respect to energy of the average waveform, the normalized value being the alternating ECG morphology index; and monitoring the changes in the alternating ECG morphology index; increases in this index correlating with lower myocardial electrical stability and vice versa.
Claim 15
Dependent Claim
135 words
Apparatus for deriving an alternating ECG morphology index from a series of heartbeats for assessing relative myocardial electrical stability, comprising: analog-to-digital means for digitizing the ECG electrical signal waveform at a plurality of sample points; means for constructing sample point matrices, having rows and columns, from the digitized ECG signals; digital computer means for computing the alternating energy at each of the sample points for the series of beats; computing means for summing the alternating energy over the entire set of sample points to generate a total alternating energy; computing means for calculating energy in an average ECG electrical signal waveform; and computing means for normalizing the total alternating energy with respect to energy of the average waveform, the normalized value being the alternating ECG morphology index, this index correlating with the myocardial electrical stability.
Claim 16
Dependent Claim
135 words
Apparatus for deriving an alternating ECG morphology index from a series of heartbeats for assessing relative myocardial electrical stability, comprising: analog-to-digital means for digitizing the ECG electrical signal waveform at a plurality of sample points; means for constructing sample point matrices, having rows and columns, from the digitized ECG signals; digital computer means for computing the alternating energy at each of the sample points for the series of beats; computing means for summing the alternating energy over the entire set of sample points to generate a total alternating energy; computing means for calculating energy in an average ECG electrical signal waveform; and computing means for normalizing the total alternating energy with respect to energy of the average waveform, the normalized value being the alternating ECG morphology index, this index correlating with the myocardial electrical stability.
Claim 17
Dependent Claim
34 words
The apparatus of claim 11 further including 6-pole low-pass filtering amplifiers having a cutoff frequency of 360 Hz for receiving the ECG electrical signal waveform and passing a filtered signal to the analog-to-digital means.
Claim 18
Dependent Claim
16 words
The apparatus of claim 11 in which the computing means has a 2 Mbyte core memory.
Claim 19
Dependent Claim
13 words
The method of claim 1 wheren the physiologic waveform is a respiration waveform.
Claim 20
Dependent Claim
61 words
Method for analyzing cycle-to-cycle variability in an ECG for assessing relative myocardial electrical stability, comprising: digitizing the waveform at a plurality of sample points for each cycle; constructing two-dimensional sample point matrices, having rows and columns, from the digitzed waveform; and analyzing variability in each column of the sample point matrices to form an index correlating with the myocardial electrical stability.
Claim 21
Dependent Claim
61 words
Method for analyzing cycle-to-cycle variability in an ECG for assessing relative myocardial electrical stability, comprising: digitizing the waveform at a plurality of sample points for each cycle; constructing two-dimensional sample point matrices, having rows and columns, from the digitzed waveform; and analyzing variability in each column of the sample point matrices to form an index correlating with the myocardial electrical stability.
Claim 22
Dependent Claim
69 words
Method for analyzing cycle-to-cycle variability in a blood pressure waveform for assessing relative stability of the blood pressure waveform, comprising: digitizing the waveform at a plurality of sample points for each cycle; constructing two-dimensional sample point matrices, having rows and columns, from the digitized waveform; and analyzing variabilty in each column of the sample point matrices to form an index correlating with the stability of the blood pressure waveform.
Claim 23
Dependent Claim
69 words
Method for analyzing cycle-to-cycle variability in a blood pressure waveform for assessing relative stability of the blood pressure waveform, comprising: digitizing the waveform at a plurality of sample points for each cycle; constructing two-dimensional sample point matrices, having rows and columns, from the digitized waveform; and analyzing variabilty in each column of the sample point matrices to form an index correlating with the stability of the blood pressure waveform.
Claim 24
Dependent Claim
60 words
Method for analyzing cycle-to-cycle alternation in a physiologic waveform for assessing relative physiologic stability, comprising: digitizing the waveform at a plurality of sample points for each cycle; constructing two-dimensional sample point matrices, having rows and columns, from the digitized waveform; and analyzing alternation in each column of the sample point matrices to form an index correlating with the physiologic stability.
Claim 25
Dependent Claim
60 words
Method for analyzing cycle-to-cycle alternation in a physiologic waveform for assessing relative physiologic stability, comprising: digitizing the waveform at a plurality of sample points for each cycle; constructing two-dimensional sample point matrices, having rows and columns, from the digitized waveform; and analyzing alternation in each column of the sample point matrices to form an index correlating with the physiologic stability.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-02-07 | 1992-08-08 | 1993-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-07 | 1996-08-08 | 1997-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-07 | 2000-08-08 | 2001-02-07 | $7700.00 | Window Closed / Lapsed |