Device and method for automatic threshold setting
First Claim
1. An implantable medical device, comprising:
- a first sensor for sensing a first signal in a patient correlated to a first physiological condition;
a second sensor for sensing a second signal in the patient corresponding to a second physiological condition;
a third sensor for sensing a third signal in the patient corresponding to a third physiological condition responsive to the second physiological condition; and
control circuitry for receiving the first, second and third signals and being configured to determine a relationship between the second signal and the third signal, detect a change in the relationship between the second signal and the third signal, determine a threshold in response to detecting the change in the relationship between the second signal and the third signal, and detect an event in response to the first signal crossing the determined threshold;
wherein the first sensor signal is correlated to a thoracic fluid level, the second sensor signal is correlated to patient activity, and the third sensor signal is correlated to respiration rate, andwherein detecting a change in the relationship between the second and third signals includes determining an activity level in response to sensing an increase in thoracic fluid level and sensing an increase in a respiration rate response to activity level compared to a previously measured respiration rate response, andwherein determining the threshold includes determining a first sensor signal level corresponding to the increase in the respiration rate response.
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Accused Products
Abstract
An implantable medical device for detecting physiological events includes a first sensor for sensing a first signal in a patient correlated to a first physiological condition, a second sensor for sensing a second signal in the patient corresponding to a second physiological condition and a third sensor for sensing a third signal in the patient corresponding to a third physiological condition responsive to the second physiological condition. Control circuitry for receiving the first, second and third signals is configured to determine a relationship between the second signal and the third signal, detect a change in the relationship between the second signal and the third signal and determine a threshold in response to detecting the change in the relationship between the second signal and the third signal. A physiological event is detected in response to the first signal crossing the determined threshold.
29 Citations
24 Claims
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1. An implantable medical device, comprising:
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a first sensor for sensing a first signal in a patient correlated to a first physiological condition; a second sensor for sensing a second signal in the patient corresponding to a second physiological condition; a third sensor for sensing a third signal in the patient corresponding to a third physiological condition responsive to the second physiological condition; and control circuitry for receiving the first, second and third signals and being configured to determine a relationship between the second signal and the third signal, detect a change in the relationship between the second signal and the third signal, determine a threshold in response to detecting the change in the relationship between the second signal and the third signal, and detect an event in response to the first signal crossing the determined threshold; wherein the first sensor signal is correlated to a thoracic fluid level, the second sensor signal is correlated to patient activity, and the third sensor signal is correlated to respiration rate, and wherein detecting a change in the relationship between the second and third signals includes determining an activity level in response to sensing an increase in thoracic fluid level and sensing an increase in a respiration rate response to activity level compared to a previously measured respiration rate response, and wherein determining the threshold includes determining a first sensor signal level corresponding to the increase in the respiration rate response. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method comprising employing an implantable medical device to perform the following steps:
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sensing a first signal in a patient correlated to a first physiological condition; sensing a second signal in the patient corresponding to a second physiological condition; sensing a third signal in the patient corresponding to a third physiological condition responsive to the second physiological condition; determining a relationship between the second signal and the third signal, detecting a change in the relationship between the second signal and the third signal, determining a threshold in response to the detected change in the relationship between the second signal and the third signal, and detecting an event in response to the first signal crossing the determined threshold; wherein the first signal is correlated to a thoracic fluid level, the second signal is correlated to patient activity, and the third signal is correlated to respiration rate, and wherein detecting a change in the relationship between the second and third signals includes determining an activity level in response to sensing an increase in thoracic fluid level and sensing an increase in a respiration rate response to the activity level compared to a previously measured respiration rate response, and wherein determining the threshold includes determining a first sensor signal level corresponding to the increase in the respiration rate response. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A non-transitory computer-readable medium for storing a set of instructions which when implemented in an implantable medical device system including a microprocessor cause the system to:
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sense a first signal in a patient correlated to a first physiological condition; sense a second signal in the patient corresponding to a second physiological condition; sense a third signal in the patient corresponding to a third physiological condition responsive to the second physiological condition; determine a relationship between the second signal and the third signal, detect a change in the relationship between the second signal and the third signal, determine a threshold in response to the detected change in the relationship between the second signal and the third signal, and detect an event in response to the first signal crossing the determined threshold; wherein the first signal is correlated to a thoracic fluid level, the second signal is correlated to patient activity, and the third signal is correlated to respiration rate, and wherein instructions for detecting a change in the relationship between the second and third signals include instructions for determining an activity level in response to sensing an increase in thoracic fluid level and sensing an increase in a respiration rate response to the activity level compared to a previously measured respiration rate response, and wherein instructions for the threshold include instructions for determining a first sensor signal level corresponding to the increase in the respiration rate response. - View Dependent Claims (14, 15, 16, 17, 18)
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19. An implantable medical device, comprising:
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means for sensing a first signal in a patient correlated to a first physiological condition; means for sensing a second signal in the patient corresponding to a second physiological condition; means for sensing a third signal in the patient corresponding to a third physiological condition responsive to the second physiological condition; means for determining a relationship between the second signal and the third signal, means for detecting a change in the relationship between the second signal and the third signal, means for determining a threshold in response to the detected change in the relationship between the second signal and the third signal, and means for detecting an event in response to the first signal crossing the determined threshold; wherein the first sensor signal is correlated to a thoracic fluid level, the second sensor signal is correlated to patient activity, and the third sensor signal is correlated to respiration rate, and wherein detecting a change in the relationship between the second and third signals includes determining an activity level in response to sensing an increase in thoracic fluid level and sensing an increase in a respiration rate response to activity level compared to a previously measured respiration rate response, and wherein determining the threshold includes determining a first sensor signal level corresponding to the increase in the respiration rate response. - View Dependent Claims (20, 21, 22, 23, 24)
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Specification