Active implantable medical device enslaved to a signal of acceleration
First Claim
1. An active implantable medical device capable of functioning in an enslaved mode, said device comprising:
- a measurement circuit comprising at least one sensor responsive to an acceleration and having an acceleration signal representative of said acceleration and a derivation circuit responsive to the acceleration signal for deriving a module of the acceleration signal;
circuitry for determining, in response to the module of the acceleration signal, a parameter of enslavement (S) of at least one function of the device; and
means for detecting increases or decrease in the acceleration signal;
means for limiting the module of the signal of acceleration when an increase in the signal of acceleration is detected by the means for detecting increases or decreases in the acceleration signal, resulting in a limited module of the signal of acceleration.
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Accused Products
Abstract
An active implantable medical device, particularly a cardiac pacemaker, which is enslaved to a signal representative of acceleration, having a measuring circuit (10) comprising at least one sensor (12) delivering a signal of acceleration, and circuits (22-24) to deliver, in response to the signal of acceleration, a parameter of enslavement of at least one function of the device, particularly that of a cardiac stimulation frequency. According to the invention, a circuit (24) operates to limit, in the detection of increase in acceleration, a value linked to the module of the signal of acceleration. Preferably, the limitation is operated on a value proportional to the square of the signal of acceleration, more particularly on a quadratic sum of individual acceleration components (Xi, Yi, Zi) according to at least two distinct axes delivered by a respective number of sensors.
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Citations
19 Claims
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1. An active implantable medical device capable of functioning in an enslaved mode, said device comprising:
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a measurement circuit comprising at least one sensor responsive to an acceleration and having an acceleration signal representative of said acceleration and a derivation circuit responsive to the acceleration signal for deriving a module of the acceleration signal; circuitry for determining, in response to the module of the acceleration signal, a parameter of enslavement (S) of at least one function of the device; and means for detecting increases or decrease in the acceleration signal; means for limiting the module of the signal of acceleration when an increase in the signal of acceleration is detected by the means for detecting increases or decreases in the acceleration signal, resulting in a limited module of the signal of acceleration. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of controlling an active implantable medical device having an enslaved function, comprising:
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detecting a signal corresponding to acceleration along at least a first axis; determining a module of the signal of acceleration; determining an increase in patient activity in response to an increase in said acceleration signal; determining a parameter (S) of enslavement of at least one function of the device in response to said determined module; and
,limiting in response to the determined increase in acceleration, the increase in acceleration signal to said function via the module. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A pacemaker having a controllable stimulation frequency controlled by a control parameter related to the patient'"'"'s effort, comprising:
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a pacemaker box having a flat surface for implanting in a vertical orientation in a patient; first means for measuring a first signal corresponding to an acceleration due to patient effort along a first axis; second means for measuring a second signal corresponding to acceleration due to patient effort along a second axis, wherein the first and second axes are perpendicular to one another and parallel to said flat surface of the pacemaker box; means for providing a module of a signal of acceleration from the first and second signals; means for computing the control parameter for controlling the stimulation frequency based on the first and second signals; means for detecting an increase in said first and said second acceleration signals; and means for limiting a value utilized in providing the module of the signal of acceleration in response to the detected increase in acceleration signals.
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18. In a pacemaker having a controllable stimulation frequency, a method for providing a control parameter related to the effort of a patient, comprising the steps of:
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providing a pacemaker box with a flat surface for implantation in a patient so that said surface is disposed in a vertical orientation; measuring first and second signals corresponding to acceleration caused by patient effort, along first and second axes which are perpendicular to one another and parallel to said flat surface of the pacemaker box; providing a module of a signal of acceleration from the first and second signals; computing the control parameter based on the first and second signals; and providing said control parameter for controlling the pacemaker stimulation frequency; determining an increasing acceleration; and limiting a value utilized in providing the module of the signal of acceleration in response to said determined increase in acceleration.
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19. A method for calculating a control parameter related to a patient'"'"'s effort for use in controlling a stimulation frequency of a pacemaker comprising:
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a) measuring first and second signals corresponding to the acceleration along first and second axes which are perpendicular to one another; b) providing a sum of absolute values of the first and second signals as a third signal; and c) integrating the third signal over a time period and providing said integrated third signal as the control parameter used to control the stimulation frequency of the pacemaker; d) determining an increase in acceleration via said first and said second signals; and e) limiting the third signal in response to the determined increase in acceleration.
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Specification