Rate responsive cardiac pacemaker
First Claim
1. A rate responsive cardiac pacemaker for implantation in a patient, comprisingactivity sensor means for converting mechanical movements of the patient to an electrical signal representative thereof,means responsive to said electrical signal for passing only a portion thereof in a frequency range below 4 Hz to discriminate against signal components arising from other than physical activity of the patient,processing means responsive to the passed portion of the signal to recover therefrom a predetermined variable signal component other than frequency of amplitude crossings relative to a threshold value, for producing an output signal representative of true physical body activity, andmeans responsive to said output signal for generating pulses at a rate that varies depending on said predetermined signal component to stimulate the patient'"'"'s heart at a rate according to the state of true physical body activity of thee patient.
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Accused Products
Abstract
An implantable variable rate pacemaker adaptive to patient exercise detects movements of the patient, and discriminates between detected movements indicative of true physical exercise by the patient and detected movements which are not true physical exercise. An activity sensor converts mechanical movements of the patient to an electrical signal representative thereof. Only a portion of the electrical signal in a frequency range below 4 Hz is processed by the pacemaker'"'"'s electrical circuitry, to discriminate against signal components arising from other than physical exercise of the patient. As a result of this signal processing, a predetermined variable signal component is recovered, other than frequency of amplitude crossings relative to a threshold value, to produce an output signal representative of true physical body exercise. The pacemaker responds to this output signal by generating pulses at a rate that varies depending on the predetermined signal component, to stimulate the patient'"'"'s heart at a rate according to the state of true physical exercise of the patient.
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Citations
10 Claims
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1. A rate responsive cardiac pacemaker for implantation in a patient, comprising
activity sensor means for converting mechanical movements of the patient to an electrical signal representative thereof, means responsive to said electrical signal for passing only a portion thereof in a frequency range below 4 Hz to discriminate against signal components arising from other than physical activity of the patient, processing means responsive to the passed portion of the signal to recover therefrom a predetermined variable signal component other than frequency of amplitude crossings relative to a threshold value, for producing an output signal representative of true physical body activity, and means responsive to said output signal for generating pulses at a rate that varies depending on said predetermined signal component to stimulate the patient'"'"'s heart at a rate according to the state of true physical body activity of thee patient.
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10. A rate responsive cardiac pacermaker for implantation in a patient, comprising
activity sensor means responsive to movements of the patient for generating an electrical signal representative thereof, means responsive to said electrical signal for detecting a preselected component thereof in a frequency range below 4 Hz to distinguish true physical exercise by the patient from other movements of the patient, and means responsive to variation of the detected component other than the number of times the amplitude of said electrical signal moves above and below a threshold level in a preselected interval, for generating pulses at a rate that varies according to the variation of the detected component, whereby the pace the patient'"'"'s heart rate according to the state of true physical exercise of the patient.
Specification