摘要 |
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.
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