Method for adapting the stimulation frequency of a heart pacemaker to the burden of the patient
First Claim
1. In a method for adapting the stimulation frequency of a heart pacemaker to the burden of a patient, including the steps of acquiring a measured value dependent on the cardiac minute output, changing the stimulation frequency during defined time intervals dependent on whether said measured value dependent on the cardiac minute volume changes, deriving a regulating variable from a succession of said measured values, and selecting a characteristic that best represents the relationship between the regulating variable and stimulation frequency in accord with this measured value change from among a plurality of stored characteristics respectively representing different relationships between the regulating variable and stimulation frequency, the improvement comprising the steps of identifying a series of chronologically spaced optimization intervals, periodically changing the stimulation frequency during each optimization interval, acquiring a series of said measured values dependent on the cardiac minute output respectively at times which are phase-synchronized with the change in stimulation frequency, and updating the selection of said characteristic that best represents the relationship between the regulating variable and stimulation frequency using said measured values acquired during said optimization interval.
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Abstract
During optimization intervals prescribed by the heart pacemaker, the stimulation frequency is periodically changed and an acquisition of a measured value that is dependent on the cardiac minute output is respectively phase-synchronized with the change in stimulation frequency. An identification is thereby made whether the measured value that is dependent on the cardiac minute output changes given the change of the stimulation frequency. A number of curves are stored representing different relationships between a regulating variable, derived from the measured value, and the stimulation frequency. The stimulation frequency of the pacemaker is set based on one of these curves, as selected by an optimization controller to which the regulating variable is supplied. If the change in the measured valued as acquired during the optimization intervals indicates that the currently-selected curve is no longer accurate, the optimization controller selects another curve from among the stored curves which best represents the current relationship between the regulating variable and the stimulation frequency.
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Citations
13 Claims
- 1. In a method for adapting the stimulation frequency of a heart pacemaker to the burden of a patient, including the steps of acquiring a measured value dependent on the cardiac minute output, changing the stimulation frequency during defined time intervals dependent on whether said measured value dependent on the cardiac minute volume changes, deriving a regulating variable from a succession of said measured values, and selecting a characteristic that best represents the relationship between the regulating variable and stimulation frequency in accord with this measured value change from among a plurality of stored characteristics respectively representing different relationships between the regulating variable and stimulation frequency, the improvement comprising the steps of identifying a series of chronologically spaced optimization intervals, periodically changing the stimulation frequency during each optimization interval, acquiring a series of said measured values dependent on the cardiac minute output respectively at times which are phase-synchronized with the change in stimulation frequency, and updating the selection of said characteristic that best represents the relationship between the regulating variable and stimulation frequency using said measured values acquired during said optimization interval.
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10. The improvement of 8, the upper limit value fmax when the calculation of the measured value changes lies between -A1 and A1 in two successive optimization intervals and the upper limit fmax has reached said lowest, prescribed value.
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