Patent US5842997A successfully refreshed from Google Patents.
US5842997A
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Non-invasive, dynamic tracking of cardiac vulnerability by simultaneous analysis of heart rate variability and T-wave alternans
Assignee: Georgetown University
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Filing: 1997-04-30
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Granted: 1998-12-01
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Expires: 2017-04-30
Abstract
Abstract A method and an apparatus for the non-invasive, dynamic tracking and diagnosing of cardiac vulnerability to ventricular fibrillation are disclosed. T-wave alternans and heart rate variability are simultaneously evaluated. T-wave alternation is an absolute predictor of cardiac electrical stability. Heart rate variability is a measure of autonomic influence, a major factor in triggering cardiac arrhythmias. By simultaneously analyzing both phenomena, the extent and cause of cardiac vulnerability can be assessed.
Inventors
- 👤 Richard L. Verrier
- 👤 Bruce D. Nearing
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 16:02
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/24; A61B5/316; A61B5/318; A61B5/346; A61B5/349; A61B5/02; A61B5/024; A61B5/02405; A61B5/352; A61B5/355; A61B5/36; A61B5/363; A61B5/40; A61B5/4029; A61B5/4035; A61B5/48; A61B5/4884; A61B5/72; A61B5/7271; A61B5/7275; G; G16; G16H; G16H50/00; G16H50/30
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
83 words
A method for assessing cardiac vulnerability comprising the steps of: receiving an ECG signal; analyzing T-waves in said ECG signal to estimate an amplitude of beat-to-beat alternation, said amplitude of beat-to-beat alternation representing cardiac electrical stability; analyzing R--R intervals in said ECG signal to estimate a magnitude of heart rate variability, said magnitude of heart rate variability indicating neural influence on the heart; and analyzing said amplitude of beat-to-beat alternation and said magnitude of heart rate variability to assess said cardiac electrical stability.
Claim 2
Independent Claim
83 words
A method for assessing cardiac vulnerability comprising the steps of: receiving an ECG signal; analyzing T-waves in said ECG signal to estimate an amplitude of beat-to-beat alternation, said amplitude of beat-to-beat alternation representing cardiac electrical stability; analyzing R--R intervals in said ECG signal to estimate a magnitude of heart rate variability, said magnitude of heart rate variability indicating neural influence on the heart; and analyzing said amplitude of beat-to-beat alternation and said magnitude of heart rate variability to assess said cardiac electrical stability.
Claim 3
Dependent Claim
53 words
The method of claim 1, wherein said step of receiving an ECG signal comprises the following steps: placing a precordial ECG lead on the surface of a subject's body proximate to the subject's heart to sense said ECG signal; amplifying said ECG signal; low-pass filtering said ECG signal; and sampling said ECG signal.
Claim 4
Dependent Claim
102 words
The method of claim 2, wherein said step of analyzing T-waves comprises the following steps: predicting the location in said ECG signal of the T-wave in each R--R interval; partitioning each T-wave in said ECG signal into a plurality of time divisions; summing the samples in each of said time divisions of said ECG signal; forming a time series for each of said time divisions, each time series including corresponding sums from corresponding time divisions from successive ones of said T-waves; and performing dynamic estimation on each said time series to estimate the amplitude of beat-to-beat alternation for each said time division.
Claim 5
Dependent Claim
21 words
The method of claim 3, wherein said step of performing dynamic estimation includes performing complex demodulation on each said time series.
Claim 6
Dependent Claim
117 words
The method of claim 2, wherein said step of analyzing R--R intervals comprises the following steps: locating the peak amplitude in each R--R interval to find the apex of each R-wave; computing the time between successive R-waves to determine a magnitude of each said R--R interval; forming a time series with said magnitudes of said R--R intervals; performing dynamic estimation on said time series to estimate a magnitude of a high frequency component of heart rate variability and to estimate a magnitude of a low frequency component of heart rate variability; and forming a ratio of said magnitudes of said low frequency and said high frequency components of heart rate variability, said ratio indicating sympathetic neural activity.
Claim 7
Dependent Claim
20 words
The method of claim 5, wherein said step of performing dynamic estimation includes performing complex demodulation on said time series.
Claim 8
Independent Claim
89 words
An apparatus for assessing cardiac vulnerability by simultaneously analyzing T-wave alternation and heart rate variability in an ECG, said apparatus comprising: means for analyzing T-waves in said ECG to determine an amplitude of beat-to-beat alternation; means for computing the magnitude of each R--R interval to determine a heart rate; means for analyzing said heart rate to determine a magnitude of variability therein, said magnitude of variability indicating neural influence on said heart; and means for presenting said amplitude of beat-to-beat alternation and said magnitude of variability to a user.
Claim 9
Independent Claim
89 words
An apparatus for assessing cardiac vulnerability by simultaneously analyzing T-wave alternation and heart rate variability in an ECG, said apparatus comprising: means for analyzing T-waves in said ECG to determine an amplitude of beat-to-beat alternation; means for computing the magnitude of each R--R interval to determine a heart rate; means for analyzing said heart rate to determine a magnitude of variability therein, said magnitude of variability indicating neural influence on said heart; and means for presenting said amplitude of beat-to-beat alternation and said magnitude of variability to a user.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-11-30 | 2002-06-01 | 2002-12-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-11-30 | 2006-06-01 | 2006-12-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-11-30 | 2010-06-01 | 2010-12-01 | $7700.00 | Window Closed / Lapsed |