Automatic adjustment of detection rate threshold in an implantable antitachycardia therapy device
First Claim
1. An implantable antitachycardia stimulation device comprising:
- pulse generating means for generating stimulation pulses to a patient'"'"'s heart;
sensing means for sensing cardiac activity of the patient'"'"'s heart;
first physiologic sensing means for sensing a physiologic parameter indicative of a normal heart rate, and for generating a first sensor signal representative of the sensed physiologic parameter;
control means, coupled to the pulse generating means, the sensing means, and the first physiological sensing means, for providing a prescribed antitachycardia therapy through the pulse generating means and for terminating a sensed cardiac arrhythmia, the control means including;
rate detection means for detecting the heart rate of the patient based on the cardiac activity sensed through the sensing means;
threshold means for generating at least two rate zone thresholds, a low rate zone threshold signal and a high rate zone threshold signal, the low rate zone threshold signal being a function of the first sensor signal, and the high rate zone threshold signal being a prescribed amount greater than the low rate zone threshold signal at least one rate zone threshold signal as a function of the first sensor signal; and
comparator means for comparing the detected heart rate with the at least one rate zone threshold signal, for determining when the heart rate exceeds the at least one rate zone threshold signal, and for indicating that a cardiac arrhythmia is present.
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Accused Products
Abstract
An antitachycardia stimulation device that automatically adjusts its detection rate threshold as a function of a sensed physiological parameter indicative of cardiac rate. The implantable antitachycardia stimulation device includes heart rate detection circuitry and antitachycardia therapy circuitry for applying a specific antitachycardia therapy in the event that the detected heart rate falls within at least one tachycardia rate zone. The tachycardia rate zone is defined by a lower threshold limit, and may also be defined by an upper threshold limit if more than one rate zone is used. The lower threshold limit is automatically adjusted as a function of an independently sensed physiological parameter that predicts a normal or natural change in the heart rate. If more then one rate zone is used, other threshold limits may also be adjusted automatically as a separate function of the same sensed physiological parameter. In one embodiment of the invention, the implantable stimulation device comprises a rate-responsive pacemaker, and the sensed physiological parameter used to adjust the rate threshold limit(s) is also used to define a sensor indicated rate signal to control the pacing rate of the pacemaker.
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Citations
39 Claims
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1. An implantable antitachycardia stimulation device comprising:
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pulse generating means for generating stimulation pulses to a patient'"'"'s heart; sensing means for sensing cardiac activity of the patient'"'"'s heart; first physiologic sensing means for sensing a physiologic parameter indicative of a normal heart rate, and for generating a first sensor signal representative of the sensed physiologic parameter; control means, coupled to the pulse generating means, the sensing means, and the first physiological sensing means, for providing a prescribed antitachycardia therapy through the pulse generating means and for terminating a sensed cardiac arrhythmia, the control means including; rate detection means for detecting the heart rate of the patient based on the cardiac activity sensed through the sensing means; threshold means for generating at least two rate zone thresholds, a low rate zone threshold signal and a high rate zone threshold signal, the low rate zone threshold signal being a function of the first sensor signal, and the high rate zone threshold signal being a prescribed amount greater than the low rate zone threshold signal at least one rate zone threshold signal as a function of the first sensor signal; and comparator means for comparing the detected heart rate with the at least one rate zone threshold signal, for determining when the heart rate exceeds the at least one rate zone threshold signal, and for indicating that a cardiac arrhythmia is present. - View Dependent Claims (2, 3, 4, 5)
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6. An implantable antitachycardia stimulation device comprising:
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pulse generating means for generating stimulation pulses to a patient'"'"'s heart; sensing means for sensing cardiac activity of the patient'"'"'s heart; first physiologic sensing means for sensing a physiologic parameter indicative of a normal heart rate, and for generating a first sensor signal representative of the sensed physiologic parameter; control means, coupled to the pulse generating means, the sensing means, and the first physiological sensing means, for providing a prescribed antitachycardia therapy through the pulse generating means and for terminating a sensed cardiac arrhythmia, the control means including; rate detection means for detecting the heart rate of the patient based on the cardiac activity sensed through the sensing means; threshold means for generating at least two rate zone thresholds, a low rate zone threshold signal and a high rate zone threshold signal, the low rate zone threshold signal being a first function of the first sensor signal, and the high rate zone threshold signal being a second function of the first sensor signal; and comparator means for comparing the detected heart rate with the at least one rate zone threshold signal, for determining when the heart rate exceeds the at least one rate zone threshold signal, and for indicating that a cardiac arrhythmia is present. - View Dependent Claims (7, 8, 9, 10)
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11. An implantable antitachycardia stimulation device comprising:
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pulse generating means for generating stimulation pulses to a patient'"'"'s heart; sensing means for sensing cardiac activity of the patient'"'"'s heart; first physiologic sensing means for sensing a physiologic parameter indicative of a normal heart rate, and for generating a first sensor signal representative of the sensed physiologic parameter; second physiologic sensing means for sensing a second physiologic parameter of the heart, and for generating a second sensor signal representative of the second physiolgic parameter; rate-responsive pacing means for determining a sensor indicated rate (SIR) signal based on the second sensor signal, and for controlling the rate of stimulation pulses provided by the pulse generating means according to the sensor indicated rate; control means, coupled to the pulse generating means, the sensing means, and the first physiological sensing means, for providing a prescribed antitachycardia therapy through the pulse generating means and for terminating a sensed cardiac arrhythmia, the control means including; rate detection means for detecting the heart rate of the patient based on the cardiac activity sensed through the sensing means; threshold means for generating at least one rate zone threshold signal as a function of the first sensor signal; and comparator means for comparing the detected heart rate with the at least one rate zone threshold signal, for determining when the heart rate exceeds the at least one rate zone threshold signal, and for indicating that a cardiac arrhythmia is present. - View Dependent Claims (12, 13, 14)
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15. An implantable antitachycardia therapy device, comprising:
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heart rate detection means for detecting a heart rate; antitachycardia therapy means for generating stimulation pulses for application to a heart when the detected heart rate exceeds a first threshold signal; physiologic sensing means for generating a sensor signal as a function of a sensed physiologic parameter of the heart; and processing means, coupled to the physiologic sensing means and the heart rate detection means, for generating the first threshold signal such that the first threshold signal assumes a minimum value if the sensor signal is less than a low sensor signal value, and the first threshold signal assumes a maximum value if the sensor signal is greater than a high sensor signal value and wherein the relationship between the sensor signal and the first threshold signal intermediate the low sensor signal value and the high sensor signal value is linear. - View Dependent Claims (16, 17, 18, 19)
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20. An implantable antitachycardia therapy device, comprising:
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heart rate detection means for detecting a heart rate; antitachycardia therapy means for generating stimulation pulses for application to a heart when the detected heart rate exceeds a first threshold signal; physiologic sensing means for generating sensor signal as a function of a sensed physiologic parameter of the heart; and processing means, coupled to the physiologic sensing means and the heart rate detection means, for generating the first threshold signal as a prescribed function of the sensor signal, wherein the prescribed function is defined such that the first threshold signal assumes a minimum value if the sensor signal is less than a low sensor signal value and assumes a maximum value if the sensor signal is greater than a high sensor signal value and assumes one of a plurality of threshold values intermediate the minimum value and the maximum value depending upon which of a respective plurality of sensor signal reference values intermediate the low and high sensor signal values is exceeded by the sensor signal. - View Dependent Claims (21, 22, 23, 24)
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25. A method for adjusting the detection rate threshold in an implantable antitachycardia therapy device, the device including rate detection means for detecting a heart rate, sensor means for sensing a physiologic parameter, and antitachycardia therapy means for selectively generating a prescribed stimulation sequence for terminating a sensed tachycardia, the method comprising the steps of:
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(a) detecting the heart rate with the rate detection means; (b) sensing the physiologic parameter with the sensor means; (c) automatically defining a detection rate threshold signal by defining a minimum detection rate threshold signal corresponding to physiologic parameters less than a low physiologic parameter, defining a maximum detecting rate threshold signal corresponding to physiologic parameters greater than a high physiologic parameter and defining the detection rate threshold signal to assume a linear relationship relative to the sensed physiologic parameter for physiologic parameters intermediate the low and high physiologic parameters; (d) determining if the sensed heart rate is greater than the detection rate threshold signal; (e) invoking a programmed mode of operation of the therapy device in the event that the sensed heart rate is less than the detection rate threshold signal; and (f) invoking an antitachycardia therapy node of operation of the therapy device in the event that the sensed heart rate is greater than the detection rate threshold signal; whereby the detection rate threshold signal is automatically adjusted as a function of the sensed physiologic parameter, and further whereby the antitachycardia therapy mode is invoked only when the detected heart rate exceeds the adjusted detection rate threshold signal. - View Dependent Claims (26)
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27. An implantable antitachycardia therapy device, comprising:
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heart rate detection means for detecting a heart rate; antitachycardia therapy means for generating stimulation pulses for application to a heart when the detected heart rate exceeds a first threshold signal; physiologic sensing means for generating a sensor signal as a function of a sensed physiologic parameter of the heart; and processing means, coupled to the physiologic sensing means and the heart rate detection means, for generating at least a low rate zone threshold signal and a high rate zone threshold signal, the low rate zone threshold signal being a first function of the sensor signal, and the high rate zone thresold signal being a second function of the sensor signal. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34)
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35. A method for adjusting the detection rate threshold in an implantable antitachycardia therapy device, the device including rate detection means for detecting a heart rate, sensor means for sensing a physiologic parameter, and antitachycardia therapy means for selectively generating a prescribed stimulation sequence for terminating a sensed tachyeardia, the method comprising the steps of:
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(a) detecting the heart rate with the rate detection means; (b) sensing the physiologic parameter with the sensor means; (c) automatically defining at least two rate zone detection thresholds, a low rate zone detection threshold signal defined as a first function of the physiologic parameter sensed by the sensor means and a high rate zone detection threshold signal defined as a second function of the physiologic parameter sensed by the sensor means; (d) determining if the sensed heart rat is greater than the low rate zone detection threshold signal; (e) invoking a programmed mode of operation of the therapy device in the event that the sensed heart rate is less than the low rate zone detection threshold signal; and (f) invoking an antitachycardia therapy mode of operation of the therapy device in the event that the sensed heart rate is greater than the detection rate threshold signal; and whereby the low rate zone detection threshold signal is automatically adjusted as a function of the sensed physiologic parameter, and further whereby the antitachycardia therapy mode is invoked only when the detected heart rate exceeds the adjusted low rate zone detection threshold signal. - View Dependent Claims (36, 37, 38, 39)
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Specification