Implantable medical device with automatic ischemia threshold determination
First Claim
1. An implantable medical device (IMD) comprising:
- at least a pair of pacing electrodes;
a pacing therapy delivery circuit operatively coupled to the pacing electrodes and configured to provide pacing signals to the pacing electrodes at a pacing rate;
a patient activity sensor coupled to the pacing therapy delivery circuit;
a patient input detector adapted to receive a patient-triggered telemetry signal;
an ischemia sensor; and
controller means for controlling operation of the pacing therapy delivery circuit, wherein the controller means periodically causes an ischemia threshold test to be performed when the patient activity sensor indicates a patient is at rest, wherein the controller means causes the pacing therapy delivery circuitry to increase the pacing rate over time until a feedback signal from either the patient input detector or the ischemia sensor is received, then causes the pacing therapy delivery circuitry to decrease the pacing rate, and causes an ischemia threshold value to be stored based upon the pacing rate at the time the feedback signal was received, wherein the controller adjusts an upper pacing rate limit for the pacing therapy delivery circuit based upon the ischemia threshold value.
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Accused Products
Abstract
An implantable medical device (IMD) performs periodic testing of a patient to determine ischemia threshold information. At selected times while the patient is at rest, the IMD increases the pacing rate over time until it receives feedback either from the patient or from an ischemia sensor. The IMD determines the threshold based upon the pacing rate at the time when the feedback was received. The threshold information can be used to adjust the upper pacing rate that can be used during rate adaptive pacing, to determine the effects of drug therapy, and to provide a general indication of the state of coronary artery disease in the patient. The periodic increase of pacing rate to the ischemic zone also provides a preconditioning of the myocardium to allow the patient greater exercise benefit without angina.
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Citations
21 Claims
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1. An implantable medical device (IMD) comprising:
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at least a pair of pacing electrodes; a pacing therapy delivery circuit operatively coupled to the pacing electrodes and configured to provide pacing signals to the pacing electrodes at a pacing rate; a patient activity sensor coupled to the pacing therapy delivery circuit; a patient input detector adapted to receive a patient-triggered telemetry signal; an ischemia sensor; and controller means for controlling operation of the pacing therapy delivery circuit, wherein the controller means periodically causes an ischemia threshold test to be performed when the patient activity sensor indicates a patient is at rest, wherein the controller means causes the pacing therapy delivery circuitry to increase the pacing rate over time until a feedback signal from either the patient input detector or the ischemia sensor is received, then causes the pacing therapy delivery circuitry to decrease the pacing rate, and causes an ischemia threshold value to be stored based upon the pacing rate at the time the feedback signal was received, wherein the controller adjusts an upper pacing rate limit for the pacing therapy delivery circuit based upon the ischemia threshold value. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of performing ischemia threshold testing of a patient with coronary artery disease, the method comprising:
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determining that the patient is at rest; increasing a pacing rate of pacing signals delivered to the patient in response to a determination that the patient is at rest; receiving a feedback signal; decreasing the pacing rate of the pacing signals; and storing an ischemia threshold value based upon the pacing rate when the feedback signal was received; and adjusting an upper pacing rate limit for rate-adaptive pacing based upon the ischemia threshold value. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method of determining an ischemia threshold of a patient, the method comprising:
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determining whether the patient is at rest; providing pacing pulses at an increasing pacing rate in response to the determination that the patient is at rest until ischemia is detected; and determining an ischemia threshold value based upon the pacing rate when ischemia is detected; and determining an upper pacing rate limit based upon the ischemia threshold value. - View Dependent Claims (14, 15, 16)
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17. An implantable medical device (IMD) comprising:
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at least a pair of pacing electrodes; a pacing therapy delivery circuit operatively coupled to the pacing electrodes and configured to provide pacing signals to the pacing electrodes at a pacing rate; an ischemia sensor providing a feedback signal; a patient activity sensor coupled to the pacing therapy delivery circuit; and controller means for controlling operation of the pacing therapy delivery circuit, wherein, responsive to the patient activity sensor indicating the patient is at rest the controller means causes the pacing therapy delivery circuitry to increase the pacing rate over time until a feedback signal from the ischemia sensor is received, then causes the pacing therapy delivery circuitry to decrease the pacing rate, and causes an ischemia threshold value to be stored based upon the pacing rate at the time the feedback signal was received; and wherein the controller adjusts an upper pacing rate limit for the pacing therapy delivery circuit based upon the ischemia threshold value. - View Dependent Claims (18, 19)
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20. An implantable medical device (IMD) comprising:
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at least a pair of pacing electrodes; a pacing therapy delivery circuit operatively coupled to the pacing electrodes and configured to provide pacing signals to the pacing electrodes at a pacing rate; a patient activity sensor coupled to the pacing therapy delivery circuit; a patient input detector adapted to receive a patient-triggered feedback signal; controller means for controlling operation of the pacing therapy delivery circuit, wherein, responsive to the patient activity sensor indicating the patient is at rest the controller means causes the pacing therapy delivery circuitry to increase the pacing rate over time until a feedback signal from the patient input detector is received, then causes the pacing therapy delivery circuitry to decrease the pacing rate, and causes an ischemia threshold value to be stored based upon the pacing rate at the time the feedback signal was received; and wherein the controller adjusts an upper pacing rate limit for the pacing therapy delivery circuit based upon the ischemia threshold value. - View Dependent Claims (21)
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Specification