US5772604A
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Method, system and apparatus for determining prognosis in atrial fibrillation
Assignee: Emory University
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Filing: 1997-03-14
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Granted: 1998-06-30
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Expires: 2017-03-14
Abstract
Abstract A system, apparatus and method for determining prognosis in atrial fibrillation non-invasively detects electrical activity of the heart with external electrodes, such as with ECG leads. The diagnostic system, apparatus and method provide a non-invasive technique to classify the severity of atrial fibrillation according to peak frequency of the fibrillation, and provide useful information for treatment of the atrial fibrillation, including the prediction of conversion with ibutilide, and the estimation of time to recurrence after cardioversion.
Inventors
- 👤 Jonathan J. Langberg
- 👤 Andreas Bollmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:13
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/24; A61B5/316; A61B5/318; A61B5/346; A61B5/349; A61B5/361; A61B5/35; A61B5/72; A61B5/7235; A61B5/7264; A61B5/7232; A61B5/7253; A61B5/7257; G; G16; G16H; G16H50/00; G16H50/20
Claims Analysis
Total Claims: 84
Claim 1
Independent Claim
76 words
A system for classifying atrial fibrillation, comprising: means for receiving electrical signals indicative of a heart's activity; means for processing the electrical signals to remove ventricular activity from the electrical signals and to output a fibrillatory baseline signal; means for transforming the fibrillatory baseline signal into a set of frequency domain signals; means for detecting a peak frequency within the set of frequency domain signals; and means for classifying atrial fibrillation based on the peak frequency.
Claim 2
Independent Claim
76 words
A system for classifying atrial fibrillation, comprising: means for receiving electrical signals indicative of a heart's activity; means for processing the electrical signals to remove ventricular activity from the electrical signals and to output a fibrillatory baseline signal; means for transforming the fibrillatory baseline signal into a set of frequency domain signals; means for detecting a peak frequency within the set of frequency domain signals; and means for classifying atrial fibrillation based on the peak frequency.
Claim 3
Dependent Claim
39 words
The system as set forth in claim 1, wherein the receiving means comprises at least one electrode for being placed on an external surface of a patient with the electrode generating the electrical signals indicative of the heart's activity.
Claim 4
Dependent Claim
29 words
The system as set forth in claim 1, wherein the receiving means comprises at least one electrode for being placed within a patient for detecting the fibrillatory baseline signal.
Claim 5
Dependent Claim
24 words
The system as set forth in claim 1, wherein the receiving means comprises an interface for receiving digital signals indicative of the heart's activity.
Claim 6
Dependent Claim
19 words
The system as set forth in claim 4, wherein the interface receives the digital signals from a storage device.
Claim 7
Dependent Claim
19 words
The system as set forth in claim 4, wherein the interface receives the digital signals from a remote transmitter.
Claim 8
Dependent Claim
25 words
The system as set forth in claim 1, wherein the receiving means comprises an interface for receiving analog signals indicative of the heart's electrical activity.
Claim 9
Dependent Claim
19 words
The system as set forth in claim 1, wherein the interface receives the analog signals from an ECG machine.
Claim 10
Dependent Claim
47 words
The system as set forth in claim 1, wherein the means for processing the electrical signals comprises means for detecting QRST complexes in the electrical signals, means for generating one or more QRST templates, and means for subtracting QRST complexes using the one or more QRST templates.
Claim 11
Dependent Claim
28 words
The system as set forth in claim 9, wherein the means for generating the one or more templates averages the QRST complexes according to their duration in time.
Claim 12
Dependent Claim
26 words
The system as set forth in claim 1, wherein the fibrillatory baseline signal comprises a digital signal and the processing means compresses the fibrillatory baseline signal.
Claim 13
Dependent Claim
22 words
The system as set forth in claim 11, wherein the processing means applies a Hamming window when compressing the fibrillatory baseline signal.
Claim 14
Dependent Claim
34 words
The system as set forth in claim 1, wherein the means for transforming the fibrillatory baseline signal performs a Fourier transformation of the fibrillatory baseline signal to produce the set of frequency domain signals.
Claim 15
Dependent Claim
26 words
The system as set forth in claim 1, further comprising an analog-to-digital converter for converting the electrical signals into digital signals indicative of the heart's activity.
Claim 16
Dependent Claim
21 words
The system as set forth in claim 1, wherein the classifying means measures a maximum power level at the peak frequency.
Claim 17
Dependent Claim
31 words
The system as set forth in claim 15, wherein the classifying means measures a band of frequencies having power levels at or above a predetermined fraction of the maximum power level.
Claim 18
Dependent Claim
30 words
The system as set forth in claim 16, wherein the classifying means measures the band of frequencies having power levels at or above 10% that of the maximum power level.
Claim 19
Dependent Claim
37 words
The system as set forth in claim 1, wherein the classifying means measures a percentage of power of the frequency domain set of signals which is contained within a predetermined range of frequencies about the peak frequency.
Claim 20
Dependent Claim
25 words
The system as set forth in claim 18, wherein the classifying means measures the percentage of total power contained within±0.5 Hz of the peak frequency.
Claim 21
Dependent Claim
20 words
The system as set forth in claim 1, wherein the classifying means compares the peak frequency to a threshold frequency.
Claim 22
Dependent Claim
15 words
The system as set forth in claim 20, wherein the threshold frequency is 6.0 Hz.
Claim 23
Dependent Claim
18 words
The system as set forth in claim 1, further comprising means for indicating results from the classifying means.
Claim 24
Independent Claim
92 words
An apparatus for classifying atrial fibrillation, comprising: a signal processor for receiving electrical signals indicative of a heart's activity, for removing ventricular activity from the electrical signals, and for outputting a fibrillatory baseline signal; a transformation circuit for receiving the fibrillatory baseline signal and for generating a set of frequency domain signals corresponding to the fibrillatory baseline signal; and a peak detector for detecting a peak frequency within the set of frequency domain signals; wherein the signal processor classifies the atrial fibrillation based on the peak frequency detected by the peak detector.
Claim 25
Independent Claim
92 words
An apparatus for classifying atrial fibrillation, comprising: a signal processor for receiving electrical signals indicative of a heart's activity, for removing ventricular activity from the electrical signals, and for outputting a fibrillatory baseline signal; a transformation circuit for receiving the fibrillatory baseline signal and for generating a set of frequency domain signals corresponding to the fibrillatory baseline signal; and a peak detector for detecting a peak frequency within the set of frequency domain signals; wherein the signal processor classifies the atrial fibrillation based on the peak frequency detected by the peak detector.
Claim 26
Dependent Claim
34 words
The apparatus as set forth in claim 23, further comprising at least one electrode for detecting the electrical signals indicative of the heart's activity and for supplying the electrical signals to the signal processor.
Claim 27
Dependent Claim
22 words
The apparatus as set forth in claim 24, wherein the electrode is for being placed on an external surface of a patient.
Claim 28
Dependent Claim
24 words
The apparatus as set forth in claim 24, wherein the electrode is for being placed within a patient for detecting the fibrillatory baseline signal.
Claim 29
Dependent Claim
25 words
The apparatus as set forth in claim 23, further comprising an interface for supplying digital signals indicative of the heart's activity to the signal processor.
Claim 30
Dependent Claim
19 words
The apparatus as set forth in claim 27, wherein the interface receives the digital signals from a storage device.
Claim 31
Dependent Claim
19 words
The apparatus as set forth in claim 27, wherein the interface receives the digital signals from a remote transmitter.
Claim 32
Dependent Claim
22 words
The apparatus as set forth in claim 23, further comprising an interface for receiving analog signals indicative of the heart's electrical activity.
Claim 33
Dependent Claim
19 words
The apparatus as set forth in claim 30, wherein the interface receives the analog signals from an ECG machine.
Claim 34
Dependent Claim
36 words
The apparatus as set forth in claim 23, wherein the signal processor detects QRST complexes in the electrical signals, generates one or more QRST templates, and subtracts QRST complexes using the one or more QRST templates.
Claim 35
Dependent Claim
29 words
The apparatus as set forth in claim 32, wherein the signal processor generates the one or more templates by averaging the QRST complexes according to their duration in time.
Claim 36
Dependent Claim
26 words
The apparatus as set forth in claim 23, wherein the fibrillatory baseline signal comprises a digital signal and the signal processor compresses the fibrillatory baseline signal.
Claim 37
Dependent Claim
22 words
The apparatus as set forth in claim 34, wherein the signal processor applies a Hamming window when compressing the fibrillatory baseline signal.
Claim 38
Dependent Claim
29 words
The apparatus as set forth in claim 23, wherein the transformation circuit performs a Fourier transformation of the fibrillatory baseline signal to produce the set of frequency domain signals.
Claim 39
Dependent Claim
26 words
The apparatus as set forth in claim 23, further comprising an analog-to-digital converter for converting the electrical signals into digital signals indicative of the heart's activity.
Claim 40
Dependent Claim
26 words
The apparatus as set forth in claim 23, wherein the signal processor classifies the atrial fibrillation by measuring a maximum power level at the peak frequency.
Claim 41
Dependent Claim
36 words
The apparatus as set forth in claim 38, wherein the signal processor classifies the atrial fibrillation by measuring a band of frequencies having power levels at or above a predetermined fraction of the maximum power level.
Claim 42
Dependent Claim
35 words
The apparatus as set forth in claim 39, wherein the signal processor classifies the atrial fibrillation by measuring the band of frequencies having power levels at or above 10% that of the maximum power level.
Claim 43
Dependent Claim
42 words
The apparatus as set forth in claim 23, wherein the signal processor classifies the atrial fibrillation by measuring a percentage of power of the frequency domain set of signals which is contained within a predetermined range of frequencies about the peak frequency.
Claim 44
Dependent Claim
25 words
The apparatus as set forth in claim 41, wherein the signal processor measures the percentage of total power contained within±0.5 Hz of the peak frequency.
Claim 45
Dependent Claim
25 words
The apparatus as set forth in claim 23, wherein the signal processor classifies the atrial fibrillation by comparing the peak frequency to a threshold frequency.
Claim 46
Dependent Claim
15 words
The apparatus as set forth in claim 43, wherein the threshold frequency is 6.0 Hz.
Claim 47
Dependent Claim
21 words
The apparatus as set forth in claim 44, wherein the signal processor indicates results of the classification of the atrial fibrillation.
Claim 48
Independent Claim
65 words
A method for classifying atrial fibrillation, comprising the steps of: receiving electrical signals indicative of a heart's activity; processing the electrical signals to remove ventricular activity and to output a fibrillatory baseline signal; transforming the fibrillatory baseline signal into a set of frequency domain signals; detecting a peak frequency within the set of frequency domain signals; and classifying atrial fibrillation based on the peak frequency.
Claim 49
Independent Claim
65 words
A method for classifying atrial fibrillation, comprising the steps of: receiving electrical signals indicative of a heart's activity; processing the electrical signals to remove ventricular activity and to output a fibrillatory baseline signal; transforming the fibrillatory baseline signal into a set of frequency domain signals; detecting a peak frequency within the set of frequency domain signals; and classifying atrial fibrillation based on the peak frequency.
Claim 50
Dependent Claim
40 words
The method as set forth in claim 46, wherein the step of receiving comprises the step of placing at least one electrode on an external surface of a patient and detecting the electrical signals with the at least one electrode.
Claim 51
Dependent Claim
32 words
The method as set forth in claim 46, wherein the step of receiving comprises the step of placing the at least one electrode within a patient for detecting the fibrillatory baseline signal.
Claim 52
Dependent Claim
25 words
The method as set forth in claim 46, wherein the step of receiving comprises the step of receiving digital signals indicative of the heart's activity.
Claim 53
Dependent Claim
26 words
The method as set forth in claim 46, wherein the step of receiving comprises the step of receiving analog signals indicative of the heart's electrical activity.
Claim 54
Dependent Claim
41 words
The method as set forth in claim 46, wherein the step of processing comprises the steps of detecting QRST complexes in the electrical signals, generating one or more QRST templates, and subtracting QRST complexes using the one or more QRST templates.
Claim 55
Dependent Claim
31 words
The method as set forth in claim 46, wherein the fibrillatory baseline signal comprises a digital signal and the step of processing comprises a step of compressing the fibrillatory baseline signal.
Claim 56
Dependent Claim
21 words
The method as set forth in claim 52, wherein the step of processing comprises a step of applying a Hamming window.
Claim 57
Dependent Claim
38 words
The method as set forth in claim 46, wherein the step of transforming the fibrillatory baseline signal comprises a step of performing a Fourier transformation of the fibrillatory baseline signal to produce the set of frequency domain signals.
Claim 58
Dependent Claim
26 words
The method as set forth in claim 46, wherein the step of classifying comprises a step of measuring a maximum power level at the peak frequency.
Claim 59
Dependent Claim
36 words
The method as set forth in claim 55, wherein the step of classifying comprises a step of measuring a band of frequencies having power levels at or above a predetermined fraction of the maximum power level.
Claim 60
Dependent Claim
35 words
The method as set forth in claim 56, wherein the step of classifying comprises a step of measuring the band of frequencies having power levels at or above 10% that of the maximum power level.
Claim 61
Dependent Claim
42 words
The method as set forth in claim 46, wherein the step of classifying comprises a step of measuring a percentage of power of the frequency domain set of signals which is contained within a predetermined range of frequencies about the peak frequency.
Claim 62
Dependent Claim
30 words
The method as set forth in claim 58, wherein the step of classifying comprises a step of measuring the percentage of total power contained within±0.5 Hz of the peak frequency.
Claim 63
Dependent Claim
25 words
The method as set forth in claim 46, wherein the step of classifying comprises a step of comparing the peak frequency to a threshold frequency.
Claim 64
Dependent Claim
23 words
The method as set forth in claim 60, further including a step of indicating results of the step of classifying the atrial fibrillation.
Claim 65
Dependent Claim
73 words
The method as set forth in claim 46, wherein the step of classifying, a patient in atrial fibrillation with a peak frequency of less than about 6.0 Hz has a probability of substantially 100% to convert to normal sinus rhythm upon acute administration of ibutilide, whereas only about 28% of patients in atrial fibrillation with a peak frequency above about 6.0 Hz will convert to normal sinus rhythm upon acute administration of ibutilide.
Claim 66
Dependent Claim
61 words
The method as set forth in claim 46, wherein the step of classifying, a patient in atrial fibrillation with a peak frequency of less than about 6.5 Hz has about 80% probability of remaining in normal sinus rhythm for more than about 3 months after successful cardioversion, said cardioversion achieved by either electric shock or by intravenous administration of antiarrhythmic drugs.
Claim 67
Dependent Claim
57 words
The method as set forth in claim 46, wherein the step of classifying, a patient in atrial fibrillation with a peak frequency of more than about 6.5 Hz has about 80% probability of recurrent atrial fibrillation within about 3 months after successful cardioversion, said cardioversion achieved by either electric shock or by intravenous administration of antiarrhythmic drugs.
Claim 68
Dependent Claim
65 words
A computer-readable medium storing software for classifying atrial fibrillation, the software for use in performing the steps of: receiving electrical signals indicative of a heart's activity; processing the electrical signals to remove ventricular activity and to output a fibrillatory baseline signal; transforming the fibrillatory baseline signal into a set of frequency domain signals; and detecting a peak frequency within the set of frequency domain signals.
Claim 69
Dependent Claim
65 words
A computer-readable medium storing software for classifying atrial fibrillation, the software for use in performing the steps of: receiving electrical signals indicative of a heart's activity; processing the electrical signals to remove ventricular activity and to output a fibrillatory baseline signal; transforming the fibrillatory baseline signal into a set of frequency domain signals; and detecting a peak frequency within the set of frequency domain signals.
Claim 70
Dependent Claim
26 words
The computer-readable medium as set forth in claim 65, further comprising a step of classifying the severity of the atrial fibrillation based on the peak frequency.
Claim 71
Dependent Claim
44 words
The computer-readable medium as set forth in claim 65, wherein the step of processing comprises the steps of detecting QRST complexes in the electrical signals, generating one or more QRST templates, and subtracting the QRST complexes using one or more of the QRST templates.
Claim 72
Dependent Claim
24 words
The computer-readable medium as set forth in claim 65, further comprising the step of indicating results of the step of classifying the atrial fibrillation.
Claim 73
Dependent Claim
74 words
The computer-readable medium as set forth in claim 66, wherein the step of classifying, a patient in atrial fibrillation with a peak frequency of less than about 6.0 Hz has a probability of substantially 100% to convert to normal sinus rhythm upon acute administration of ibutilide, whereas only about 28% of patients in atrial fibrillation with a peak frequency above about 6.0 Hz will convert to normal sinus rhythm upon acute administration of ibutilide.
Claim 74
Dependent Claim
62 words
The computer-readable medium as set forth in claim 66, wherein the step of classifying, a patient in atrial fibrillation with a peak frequency of less than about 6.5 Hz has about 80% probability of remaining in normal sinus rhythm for more than about 3 months after successful cardioversion, said cardioversion achieved by either electric shock or by intravenous administration of antiarrhythmic drugs.
Claim 75
Dependent Claim
58 words
The computer-readable medium as set forth in claim 66, wherein the step of classifying, a patient in atrial fibrillation with a peak frequency of more than about 6.5 Hz has about 80% probability of recurrent atrial fibrillation within about 3 months after successful cardioversion, said cardioversion achieved by either electric shock or by intravenous administration of antiarrhythmic drugs.
Claim 76
Dependent Claim
27 words
The computer-readable medium as set forth in claim 66, wherein the step of classifying comprises a step of measuring a maximum power level at the peak frequency.
Claim 77
Dependent Claim
37 words
The computer-readable medium as set forth in claim 66, wherein the step of classifying comprises a step of measuring a band of frequencies having power levels at or above a predetermined fraction of the maximum power level.
Claim 78
Dependent Claim
43 words
The computer-readable medium as set forth in claim 66, wherein the step of classifying comprises a step of measuring a percentage of power of the frequency domain set of signals which is contained within a predetermined range of frequencies about the peak frequency.
Claim 79
Dependent Claim
26 words
The computer-readable medium as set forth in claim 66, wherein the step of classifying comprises a step of comparing the peak frequency to a threshold frequency.
Claim 80
Independent Claim
109 words
A method for determining suitable treatment for a patient with atrial fibrillation, comprising the steps of: (a) detecting electrical signals recorded with electrocardiogram leads placed upon the patient, said signals indicative of the heart's electrical activity; (b) processing the electrical signals to remove activity associated with ventricular activation and repolarization, by generating one or more templates for QRST complexes and subtracting one of the templates for each QRST complex with the detected electrical signals; (c) performing a Fourier transformation, including a Hamming window, on the processed electrical signals to produce a set of frequency domain signals; and (d) detecting a peak frequency within the set of frequency domain signals.
Claim 81
Independent Claim
109 words
A method for determining suitable treatment for a patient with atrial fibrillation, comprising the steps of: (a) detecting electrical signals recorded with electrocardiogram leads placed upon the patient, said signals indicative of the heart's electrical activity; (b) processing the electrical signals to remove activity associated with ventricular activation and repolarization, by generating one or more templates for QRST complexes and subtracting one of the templates for each QRST complex with the detected electrical signals; (c) performing a Fourier transformation, including a Hamming window, on the processed electrical signals to produce a set of frequency domain signals; and (d) detecting a peak frequency within the set of frequency domain signals.
Claim 82
Dependent Claim
78 words
The method as set forth in claim 76, wherein after the step (d) of detecting the peak frequency, a patient in atrial fibrillation with a peak frequency of less than about 6.0 Hz has a probability of substantially 100% to convert to normal sinus rhythm upon acute administration of ibutilide, whereas only about 28% of patients in atrial fibrillation with a peak frequency above about 6.0 Hz will convert to normal sinus rhythm upon acute administration of ibutilide.
Claim 83
Dependent Claim
66 words
The method as set forth in claim 76, wherein after the step (d) of detecting the peak frequency, a patient in atrial fibrillation with a peak frequency of less than about 6.5 Hz has about 80% probability of remaining in normal sinus rhythm for more than about 3 months after successful cardioversion, said cardioversion achieved by either electric shock or by intravenous administration of antiarrhythmic drugs.
Claim 84
Dependent Claim
62 words
The method as set forth in claim 76, wherein after the step (d) of detecting the peak frequency, a patient in atrial fibrillation with a peak frequency of more than about 6.5 Hz has about 80% probability of recurrent atrial fibrillation within about 3 months after successful cardioversion, said cardioversion achieved by either electric shock or by intravenous administration of antiarrhythmic drugs.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-06-29 | 2001-12-29 | 2002-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-06-29 | 2005-12-29 | 2006-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-06-29 | 2009-12-29 | 2010-06-30 | $7700.00 | Window Closed / Lapsed |