System and method for modulating the base rate during sleep for a rate-responsive cardiac pacemaker
First Claim
1. A rate-responsive pacemaker for administering pacing pulses to a patient'"'"'s heart, the pacemaker including memory means for storing a predetermined transfer function that correlates sensor level measurements representative of the patient'"'"'s metabolic need to heart rate, the predetermined transfer function being characterized by a base pacing rate, a maximum pacing rate, and a transition segment defining pacing rates between the base pacing rate and the maximum pacing rate, the rate-responsive pacemaker comprising:
- a pulse generator for generating pacing pulses at a selectable rate between the base pacing rate and the maximum pacing rate in accordance with the predetermined transfer curve;
a physiological sensor for generating raw sensor signals indicative of the patient'"'"'s level of metabolic need;
a processor, coupled to the pulse generator and the physiological sensor, for controlling the rate of pacing pulses, the processor including;
(a) means for processing the raw sensor signals to derive the sensor level measurements;
(b) means for determining an appropriate heart rate for the patient'"'"'s level of metabolic need based on the sensor level measurements and the corresponding heart rate defined by the predetermined transfer function;
(c) means for causing the pulse generator to generate pacing pulses at the appropriate heart rate;
(d) means for deriving first variance measurements based on the sensor level measurements, the first variance measurements being based on the difference between a current sensor level measurement and at least one earlier sensor level measurement; and
(e) means for modulating the base pacing rate in accordance with the first variance measurements.
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Accused Products
Abstract
A system and method are provided for modulating the base rate of a transfer function for a rate-responsive cardiac pacemaker. Activity sensor measurements are used to derive activity variance measurements, which in turn are used to modulate the base pacing rate. In one embodiment, a histogram is used to store activity variance measurements collected over a period of about a week. The histogram is used to derive an activity variance threshold, which is compared to current activity variance measurements to determine if the patient is sleeping. If the patient is deemed to be sleeping, the pacing rate is set to a rate that comfortably meets the patient'"'"'s low metabolic demands during sleep. In alternative embodiments, the activity variance measurements are applied to a base rate slope to modulate the base pacing rate.
447 Citations
40 Claims
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1. A rate-responsive pacemaker for administering pacing pulses to a patient'"'"'s heart, the pacemaker including memory means for storing a predetermined transfer function that correlates sensor level measurements representative of the patient'"'"'s metabolic need to heart rate, the predetermined transfer function being characterized by a base pacing rate, a maximum pacing rate, and a transition segment defining pacing rates between the base pacing rate and the maximum pacing rate, the rate-responsive pacemaker comprising:
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a pulse generator for generating pacing pulses at a selectable rate between the base pacing rate and the maximum pacing rate in accordance with the predetermined transfer curve; a physiological sensor for generating raw sensor signals indicative of the patient'"'"'s level of metabolic need; a processor, coupled to the pulse generator and the physiological sensor, for controlling the rate of pacing pulses, the processor including; (a) means for processing the raw sensor signals to derive the sensor level measurements; (b) means for determining an appropriate heart rate for the patient'"'"'s level of metabolic need based on the sensor level measurements and the corresponding heart rate defined by the predetermined transfer function; (c) means for causing the pulse generator to generate pacing pulses at the appropriate heart rate; (d) means for deriving first variance measurements based on the sensor level measurements, the first variance measurements being based on the difference between a current sensor level measurement and at least one earlier sensor level measurement; and (e) means for modulating the base pacing rate in accordance with the first variance measurements. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of providing rate-responsive pacing therapy to a patient'"'"'s heart in an implantable stimulation device, the implantable stimulation device including memory means for storing a predetermine transfer function that correlates sensor measurements representative of the patient'"'"'s metabolic need to heart rate, the predetermine transfer function being characterized by a base pacing rate, a maximum pacing rate, and a transition segment defining pacing rates between the base pacing rate and the maximum pacing rate, the method comprising the steps of:
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generating pacing pulses at a selectable rate between the base pacing rate and the maximum pacing rate in accordance with the predetermined transfer curve; sensing the patient'"'"'s level of metabolic need and generating raw sensor signals representative thereof; processing the raw sensor signals to derive the sensor measurements; determining the rate at which pacing pulses are generated based on the sensor measurements and the predetermined transfer function; processing the sensor measurements to derive first variance measurements, the first variance measurements being based on the difference between a current sensor measurement and at least one previous sensor measurement; and modulating the base pacing rate to a lower pacing rate in accordance with the first variance measurements. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A rate-responsive pacemaker for administering pacing pulses to a patient'"'"'s heart, comprising:
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a pulse generator for generating pacing pulses at a rate between a variable base rate and a maximum pacing rate; an activity sensor for generating raw sensor signals indicative of the patient'"'"'s activity level; control means for determining the rate of pacing pulses generated by the pulse generator, the control means including; (a) processing means for processing the raw sensor signals to determine activity measurements; (b) detecting means for detecting when a patient is asleep based on the activity measurements; and (c) modulating means for varying the base pacing rate between a resting rate and a sleeping rate when the patient is asleep. - View Dependent Claims (34, 35, 36, 37, 38, 39)
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40. A rate-responsive pacemaker for administering pacing pulses to a patient'"'"'s heart, comprising:
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a pulse generator for generating pacing pulses at a rate between a base rate and a maximum pacing rate; an activity sensor for generating raw sensor signals indicative of the patient'"'"'s activity level; and control means for determining the rate of pacing pulses generated by the pulse generator, the control means including; processing means for processing the raw sensor signals to determine activity measurements; and modulating means for continuously adjusting the base pacing rate based on the activity measurements.
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Specification