Detecting heart failure by monitoring the time sequence of physiological changes
First Claim
1. A system to detect a condition of worsening heart failure, the system comprising:
- a state machine circuit, configured to receive information about different first and second physiological characteristics of a subject, wherein the state machine comprises;
a state sequence of at least first, second, and third states, wherein a state represents a physiological status of the subject, and wherein the first state includes a status of post-S2 heart sound energy in a sensed electrical heart sound signal and the third state corresponds to a worsening heart failure event of the subject;
a first forward state transition from the first state to the second state in response to a first transition trigger, wherein the first transition trigger includes a change in the post-S2 heart sound energy;
a first reverse state transition from the second state to the first state in response to first of expiration of a first timer and ceasing of the first transition trigger;
a second forward state transition from the second to the third state in response to a second transition trigger associated with worsening heart failure status of the subject; and
a second reverse state transition from the third state to the second state in response to first of expiration of a second timer and ceasing of the second transition trigger, and generating an alert indicating worsening heart failure event of the subject otherwise.
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Abstract
Systems and methods for detecting heart failure by monitoring the time-sequence of physiological changes of a subject using a state machine circuit configured to receive information about physiological characteristics of the subject is described. The current state transitions between a first and a second state in response to a first transition trigger. The current state transitions between the second and first states in response to at least one of the expiration of a first timer or ceasing of the first transition trigger. The current state transitions between the second and third states in response to a second transition trigger. The current state transitions between the third and second states in response to at least one of expiration of a second timer or ceasing of the second transition trigger.
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Citations
18 Claims
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1. A system to detect a condition of worsening heart failure, the system comprising:
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a state machine circuit, configured to receive information about different first and second physiological characteristics of a subject, wherein the state machine comprises; a state sequence of at least first, second, and third states, wherein a state represents a physiological status of the subject, and wherein the first state includes a status of post-S2 heart sound energy in a sensed electrical heart sound signal and the third state corresponds to a worsening heart failure event of the subject; a first forward state transition from the first state to the second state in response to a first transition trigger, wherein the first transition trigger includes a change in the post-S2 heart sound energy; a first reverse state transition from the second state to the first state in response to first of expiration of a first timer and ceasing of the first transition trigger; a second forward state transition from the second to the third state in response to a second transition trigger associated with worsening heart failure status of the subject; and a second reverse state transition from the third state to the second state in response to first of expiration of a second timer and ceasing of the second transition trigger, and generating an alert indicating worsening heart failure event of the subject otherwise. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of controlling operation of a medical device, the method comprising:
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receiving information about different first and second physiological characteristics of an subject; forward transitioning from a first device state to a second device state in response to a first transition trigger, wherein a device state represents a physiological status of the subject, and wherein the first device state includes a status of post-S2 heart sound energy in a sensed electrical heart sound signal and the first transition trigger includes a change in the post-S2 heart sound signal energy; transitioning back from the second state to the first state in response to first of expiration of a first timer and ceasing of the first transition trigger; forward transitioning from the device second state to a third device state in response to a second transition trigger, wherein the third device state corresponds to a worsening heart failure event of the subject; transitioning back from the third state to the second state in response to first of expiration of a second timer and ceasing of the second transition trigger, and generating an alert indicating worsening heart failure event of the subject otherwise. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification