Apparatus and process for control of implantable rate-adaptive cardiac pacemaker
First Claim
1. A method of controlling an implantable cardiac pacemaker having a stimulation frequency that is a function of at least a parameter representative of the physical activity of a patient, comprising adjusting the stimulation frequency to follow a time dependent non-linear mathematical function that is an approximation of the change of the physiological cardiac rhythm.
2 Assignments
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Accused Products
Abstract
A rate-adaptive implantable cardiac pacemaker having a control parameter representative of the physical activity of the patient. The change of the stimulation frequency follows, in a manner to reproduce the natural change of the physiological cardiac rhythm, a non-linear mathematical function of time, e.g., of the type:
Fc(t)=A*(1-B*e.sup.-t/Tau)+C,
in which t is time, A, B, C and Tau are constants, and Fc(t) is the stimulation frequency as a function of time. Tau may be a different value for increasing and decreasing frequencies.
10 Citations
39 Claims
- 1. A method of controlling an implantable cardiac pacemaker having a stimulation frequency that is a function of at least a parameter representative of the physical activity of a patient, comprising adjusting the stimulation frequency to follow a time dependent non-linear mathematical function that is an approximation of the change of the physiological cardiac rhythm.
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11. An implantable rate-adaptive cardiac pacemaker having a sensor detecting at least a parameter representative of the physical activity of a patient and a processor for determining, as a function of the detected parameter, a cardiac stimulation frequency which follows, in a manner to reproduce a change of a physiological cardiac rhythm, a mathematical function of the type:
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space="preserve" listing-type="equation">Fc(t)=A*(1-B*e.sup.-t/Tau)+C,where Fc(t) is the stimulation frequency output by the pacemaker as a function of time, t is the parameter of time, and A, B, C, and Tau are constants. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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16. The apparatus according to claim 15, characterized in that the factor MULT:
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is incremented when the variation applied on the preceding escape interval is null, is reset to 1 as soon as the variation is non null, and is reset to 1 if Fc=Ftarget.
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17. The apparatus according to claim 16, characterized in that the variation of the cardiac stimulation frequency from one cycle to the following cycle is limited to a maximal value, preferably equal to 6 mn-1.
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18. A method of controlling an implantable rate-adaptive cardiac pacemaker having a delivered stimulation frequency and a calculated stimulation frequency that is periodically calculated as a function of a sensed control parameter representative of the physical activity of a patient, comprising:
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comparing an existing delivered stimulation frequency and a calculated stimulation frequency (Ftarget); and controlling the delivered stimulation frequency to change between Fstart and Ftarget as a dependent non-linear mathematical function of time, wherein said function approximates a physiological cardiac rhythm change over time. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. In an implantable rate-adaptive cardiac pacemaker having a delivered stimulation frequency and a sensor to detect a control parameter representative of the physical activity of a patient, apparatus for controlling the delivered stimulation frequency comprising:
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means for calculating a stimulation frequency corresponding to said sensed control parameter; means for comparing an existing delivered stimulation frequency (Fstart) and a calculated stimulation frequency (Ftarget); and means for controlling the delivered stimulation frequency to change between Fstart and Ftarget as a dependent non-linear mathematical function of time that approximates a physiological cardiac rhythm change over time. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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Specification