Rest/activity phase-responsive rate controlled cardiac pacer
First Claim
1. A rate controlled cardiac pacemaker comprising:
- stimulating means for stimulating the heart of a patient at a stimulation rate;
a stress sensor for sensing actual physical stress of the patient;
logic control means coupled with the stimulating means and the stress sensor, for adapting the stimulation rate to the actual physical stress of the patient;
determining means coupled with the logic control means, for determining the activity of the patient, said determining means including an activity sensor for sensing the activity state of the patient, said activity sensor having an output, and a rate control circuit having an input connected with the output of the activity sensor; and
timer means coupled with the determining means, for generating a timer output signal based on a 24-hour rhythm indicating a rest phase or an activity phase, synchronized by said activity sensor in a 24-hour rhythm with patient activity and rest phases that occur in continuous alternation, said activity sensor, in the case of the absence of activity or low activity of the patient over a long period of time, or in the case of activity which exceeds a predetermined level, respectively, emitting an output signal to an input of said timer means for synchronizing the timer means, said timer means generating the timer output signal based on the 24-hour rhythm indicating a rest phase or an activity phase, respectively, independently of the signal from said activity sensor, with a change between an activity and a rest phase, on the average, following a change of the output signals of the activity sensor picked up during a preceding time period.
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Abstract
A rate controlled cardiac pacemaker stimulates the heart of a patient at a stimulation rate and includes a stress sensor for sensing actual physical stress of the patient. The device includes control logic for adapting the stimulation rate of the pacemaker to the actual physical stress of the patient and determining circuitry for determining the activity of the patient. The determining circuitry includes an activity sensor for sensing the activity state of the patient and a rate control circuit having an input connected with an output of the activity sensor. A timer generates a signal based on a 24-hour rhythm indicating a rest phase or an activity phase, and is synchronized by the activity sensor in a 24-hour rhythm with patient activity and rest phases that occur in continuous alternation. The activity sensor, in the case of the absence of activity or low activity of the patient over a long period of time, or in the case of activity which exceeds a predetermined level, respectively, emits an output signal to an input of the timer for synchronizing the timer. The timer generates the signal based on the 24-hour rhythm indicating a rest phase or an activity phase, respectively, independently of the signal from the activity sensor, with a change between an activity and a rest phase, on the average, following a change of the output signals of the activity sensor picked up during a preceding time period.
47 Citations
18 Claims
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1. A rate controlled cardiac pacemaker comprising:
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stimulating means for stimulating the heart of a patient at a stimulation rate; a stress sensor for sensing actual physical stress of the patient; logic control means coupled with the stimulating means and the stress sensor, for adapting the stimulation rate to the actual physical stress of the patient; determining means coupled with the logic control means, for determining the activity of the patient, said determining means including an activity sensor for sensing the activity state of the patient, said activity sensor having an output, and a rate control circuit having an input connected with the output of the activity sensor; and timer means coupled with the determining means, for generating a timer output signal based on a 24-hour rhythm indicating a rest phase or an activity phase, synchronized by said activity sensor in a 24-hour rhythm with patient activity and rest phases that occur in continuous alternation, said activity sensor, in the case of the absence of activity or low activity of the patient over a long period of time, or in the case of activity which exceeds a predetermined level, respectively, emitting an output signal to an input of said timer means for synchronizing the timer means, said timer means generating the timer output signal based on the 24-hour rhythm indicating a rest phase or an activity phase, respectively, independently of the signal from said activity sensor, with a change between an activity and a rest phase, on the average, following a change of the output signals of the activity sensor picked up during a preceding time period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An evaluation circuit for detecting changes in a patient day/night activity and producing a control signal for switching off a rate control system for a cardiac pacemaker, the evaluation circuit comprising:
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an activity sensor for providing signals to the rate control system; a decoder operatively coupled to receive signals from the rate control system and produce a reference frequency signal output; a phase locked loop circuit for receiving the reference frequency signal from the decoder and producing a control signal; and a controllable switch coupled between the rate control system and a power source, the controllable switch further coupled to said phase locked loop circuit and being controlled by the control signal from said phase locked loop circuit. - View Dependent Claims (15, 16, 17)
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18. A rate controlled cardiac pacemaker comprising:
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controllable output means for stimulating a patient heart with electrical signals; control means for controlling the output means; amplifier means for receiving and amplifying signals from the patient heart; detection means for receiving the amplified signals from the amplifying means and providing detection signals; rest phase switch means for detecting phases of physical activity and rest of a patient and producing activity signals; and logic control means for receiving the activity signals from said rest phase switch means and the detection signals from said detection means, and providing control signals to said control means.
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Specification