Automated analysis of a cardiac signal based on dynamical characteristics of the cardiac signal
First Claim
1. A machine-implemented method comprising:
- obtaining a sensed cardiac signal of an organism, the sensed cardiac signal comprising a time series x(t);
applying a Hilbert (H) transform to the time series x(t) to obtain H(x(t)), wherein x(t) and H(x(t)) together forming a partial state space trajectory;
determining a speed of trajectory, for the sensed cardiac signal, from the partial state space trajectory; and
identifying physiological information concerning the organism based on a combination of first and second signal elements, the first signal element comprising a phase property or an amplitude property of the speed of trajectory, and the second signal element comprising an amplitude property of the partial state space trajectory;
wherein the determining and the identifying are performed by one or more data processing apparatus.
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Accused Products
Abstract
Systems and techniques relating to locating cardiac wave forms in a cardiac signal, and to detecting a physiological condition, such as ventricular fibrillation. In general, in one aspect, a machine-implemented method includes obtaining a sensed cardiac signal of an organism, the sensed cardiac signal comprising a time series x(t); applying a Hilbert (H) transform to the time series x(t) to obtain H(x(t)), wherein x(t) and H(x(t)) together forming a partial state space trajectory; determining a speed of trajectory, for the sensed cardiac signal, from the partial state space trajectory; and identifying physiological information concerning the organism based on a combination of first and second signal elements, the first signal element including a phase property or an amplitude property of the speed of trajectory, and the second signal element including an amplitude property of the partial state space trajectory.
152 Citations
32 Claims
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1. A machine-implemented method comprising:
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obtaining a sensed cardiac signal of an organism, the sensed cardiac signal comprising a time series x(t); applying a Hilbert (H) transform to the time series x(t) to obtain H(x(t)), wherein x(t) and H(x(t)) together forming a partial state space trajectory; determining a speed of trajectory, for the sensed cardiac signal, from the partial state space trajectory; and identifying physiological information concerning the organism based on a combination of first and second signal elements, the first signal element comprising a phase property or an amplitude property of the speed of trajectory, and the second signal element comprising an amplitude property of the partial state space trajectory; wherein the determining and the identifying are performed by one or more data processing apparatus. - View Dependent Claims (2, 3, 4, 5)
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6. A machine-readable medium encoding a computer program product operable to cause data processing apparatus to perform operations comprising:
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obtaining a sensed cardiac signal of an organism, the sensed cardiac signal comprising a time series x(t); applying a Hilbert (H) transform to the time series x(t) to obtain H(x(t)), wherein x(t) and H(x(t)) together forming a partial state space trajectory; estimating a speed of trajectory, v(i), for the sensed cardiac signal, in discrete time t≡
i, i=[0 . . . n], using finite differences in the partial state space trajectory, wherein the estimated speed of trajectory v(i) includes a first component corresponding to x(t) and a second component corresponding to H(x(t));determining from v(i), by division, a phase property of the estimated speed of trajectory v(i) in accordance with a trigonometric function of phase; and identifying physiological information concerning the organism based on the phase property. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. A machine-implemented method comprising:
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obtaining a sensed cardiac signal of an organism, the sensed cardiac signal comprising a time series x(t); applying a Hilbert (H) transform to the time series x(t) to obtain H(x(t)), wherein x(t) and H(x(t)) together forming a partial state space trajectory; determining a speed of trajectory, for the sensed cardiac signal, from the partial state space trajectory; combining an amplitude property of the partial state space trajectory with an amplitude property of the speed of trajectory to derive a momentum of trajectory; and identifying physiological information concerning the organism based on the momentum of trajectory derived from the amplitude property of the partial state space trajectory and the amplitude property of the speed of trajectory; wherein the determining, the combining, and the identifying are performed by one or more data processing apparatus. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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22. A cardiac monitoring apparatus comprising:
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an input element; a processor; and a machine-readable medium encoding instructions operable to cause the processor to perform operations comprising; obtaining, from the input element, a sensed cardiac signal of an organism; applying a Hilbert transform to the sensed cardiac signal to form a partial state space trajectory; determining a speed of trajectory, for the sensed cardiac signal, from the partial state space trajectory; combining an amplitude property of the partial state space trajectory with an amplitude property of the speed of trajectory to form a calculated signal; and identifying physiological information concerning the organism based on the calculated signal. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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Specification