Acceleration-sensitive cardiac pacemaker and method of operation
First Claim
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1. A rate adaptive pacemaker comprising:
- means for sensing a physiological parameter wherein the sensing means provides an output signal corresponding to the sensed physiological parameter;
means for providing a sensor determined interval from the output signal coupled to the sensing means and comprising means for performing analog signal processing and means for performing digital signal processing;
means for determining an actual pacing interval;
means for determining a pacing rate coupled to the means for providing the sensor determined interval and the means for determining the actual pacing interval wherein the pacing rate is a function of both the sensor determined interval and the actual pacing interval;
means for generating pacing pulses at said pacing rate; and
wherein the means for performing analog signal processing compromises;
(a) means connected to receive the output signal for chopping and modulating the output signal and providing a first modulated signal;
(b) first means for amplifying coupled to the chopping and modulating means to receive the first modulated signal and provide a first amplified output;
(c) first means for filtering having a first input coupled to receive the first amplified output and providing a first filtered output;
(d) second means for amplifying coupled to the first filtered output and providing a second amplified output;
(e) demodulator means for demodulating having an input coupled to the second amplified output and providing a demodulated output;
(f) second means for filtering having an input coupled to the demodulated output and providing a second filtered output;
(g) third means for amplifying having a first input also coupled to the second filtered output and providing a third amplified output; and
(h) means for converting analog signals to digital signals having first and second inputs coupled to the third amplified output.
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Abstract
An accelerometer based rate adaptive pacemaker generating an acceleration output signal corresponding to sensed acceleration of a patient'"'"'s body. Apparatus for providing a sensor determined interval is coupled to the acceleration sensor and the sensor determined interval is proportional to the acceleration output signal. Apparatus for determining an actual pacing interval is coupled to an apparatus for determining a generated pacing interval. The generated pacing interval is a function of both the sensor determined interval and the actual pacing interval.
189 Citations
13 Claims
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1. A rate adaptive pacemaker comprising:
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means for sensing a physiological parameter wherein the sensing means provides an output signal corresponding to the sensed physiological parameter; means for providing a sensor determined interval from the output signal coupled to the sensing means and comprising means for performing analog signal processing and means for performing digital signal processing; means for determining an actual pacing interval; means for determining a pacing rate coupled to the means for providing the sensor determined interval and the means for determining the actual pacing interval wherein the pacing rate is a function of both the sensor determined interval and the actual pacing interval; means for generating pacing pulses at said pacing rate; and wherein the means for performing analog signal processing compromises; (a) means connected to receive the output signal for chopping and modulating the output signal and providing a first modulated signal; (b) first means for amplifying coupled to the chopping and modulating means to receive the first modulated signal and provide a first amplified output; (c) first means for filtering having a first input coupled to receive the first amplified output and providing a first filtered output; (d) second means for amplifying coupled to the first filtered output and providing a second amplified output; (e) demodulator means for demodulating having an input coupled to the second amplified output and providing a demodulated output; (f) second means for filtering having an input coupled to the demodulated output and providing a second filtered output; (g) third means for amplifying having a first input also coupled to the second filtered output and providing a third amplified output; and (h) means for converting analog signals to digital signals having first and second inputs coupled to the third amplified output. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for operating a cardiac pacemaker implanted in a patient'"'"'s body comprising the steps of:
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(a) sensing acceleration of the patient'"'"'s body; (b) providing an acceleration output signal proportional to the sensed acceleration; (c) band limiting and filtering the acceleration output signal to provide a filtered accelerator output; (d) digitizing the filtered accelerator output; (e) sampling the filtered accelerator output and summing the samples over a cardiac cycle to provide an accumulated sum; (f) determining a sensor rectified average proportional to the accumulated sum divided by the number of samples in a cardiac cycle; (g) determining a sensor determined interval proportional to the sensor rectified average; (h) determining a pacing rate based in part on the sensor determined interval; and (i) generating pulses at the pacing rate. - View Dependent Claims (12, 13)
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Specification