Automatic adjustment of the control function for a rate adaptive pacemaker
First Claim
1. A method for controlling a pacemaker having a control relation between the pacing rate (FC) and a monitored physiological parameter (X) of the patient, the control relation having coefficients defining the control relation of the pacing rate having a programmed minimum rate (FC low) and a programmed maximum rate (FC max), characterized by defining a linear control relation aX+b, calculating automatically a value X low and a value X max corresponding to a minimum activity and a maximum activity in response to a measure of the physiological parameter, and recalculating automatically the values X low and X max in response to a second obtained measure of the physiological parameter so that the control relation is a line intersecting two pairs of values (FC low, X low) and (FC max, X max) and corresponds to the real needs of the patient.
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Accused Products
Abstract
A cardiac pacemaker having a pacing rate responsive to a control function of a physiological parameter indicative of activity levels. The coefficients of the function are automatically calculated and modified in response to the trend of the measured physiological parameter in order to correspond to the patient real needs. For monitoring the physiological parameter minute ventilation (VE), the basic value VE low and maximum value VE max are calculated in order to vary the slope and intercept of the straight line representative of the control relation of the pacing rate FC by the minute volume VE.
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Citations
60 Claims
- 1. A method for controlling a pacemaker having a control relation between the pacing rate (FC) and a monitored physiological parameter (X) of the patient, the control relation having coefficients defining the control relation of the pacing rate having a programmed minimum rate (FC low) and a programmed maximum rate (FC max), characterized by defining a linear control relation aX+b, calculating automatically a value X low and a value X max corresponding to a minimum activity and a maximum activity in response to a measure of the physiological parameter, and recalculating automatically the values X low and X max in response to a second obtained measure of the physiological parameter so that the control relation is a line intersecting two pairs of values (FC low, X low) and (FC max, X max) and corresponds to the real needs of the patient.
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9. In a pacemaker having a cardiac pacing rate that varies between a selected maximum rate and a selected minimum rate in response to a control function relating a monitored physiological parameter indicative of patient activity to a pacing rate, a method for adjusting the control function comprising:
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(a) providing a minimum activity value for the physiological parameter corresponding to patient activity; (b) calculating maximum activity value as a first function of the provided minimum activity value; and (c) calibrating the control function so that the provided minimum activity value relates to the selected minimum pacing rate and the calculated maximum activity value relates to the selected maximum pacing rate. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A pacemaker having a programmed minimum pacing rate (FC low) and a programmed maximum pacing rate (FC max), comprising:
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a sensor for monitoring a physiological parameter (X) indicative of patient activity; means for providing a linear control relation for providing a selected pacing rate in response to a measure of the physiological parameter having as coefficients FC low and FC max; first means for calculating automatically a value X low and a value X max in response to an obtained measure of the physiological parameter corresponding to patient minimum and maximum activity levels, respectively, said first means recalculating automatically the values X low and X max in response to a second obtained measure of the physiological parameter; and means for adjusting the linear control relation to intersect two pairs of values (FC low, X low) and (FC max, X max) to correspond to the real needs of the patient. - View Dependent Claims (28, 29, 30, 31, 32, 33)
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34. A method for controlling a pacemaker having a control relation between the pacing rate (FC) and a monitored minute volume (VE) of a patient, the control relation having coefficients defining the control relation of the pacing rate having a programmed minimum rate (FC low) and a programmed maximum rate (FC max), characterized by:
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defining a linear control relation a(VE)+b; initializing the control relation by calculating a minimum parameter VE low to be the mean value taken over a plurality of breathing cycles of the patient at rest, the plurality being selected from between 4 and 16, and providing a maximum parameter VE max; calculating automatically thereafter a value VE low and a value VE max corresponding to a minimum activity and a maximum activity in response to measures of the minute volume; and maintaining the control relation as a line intersecting two pairs of values (FC low, VE low) and (FC max, VE max) to correspond to the real needs of the patient. - View Dependent Claims (35, 36, 37, 38, 39, 40)
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41. In a pacemaker having a cardiac pacing rate that varies between a selected maximum rate and a selected minimum rate in response to a control function relating a monitored physiological parameter indicative of patient activity to a pacing rate, a method for adjusting the control function comprising:
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(a) providing a minimum activity value for the physiological parameter corresponding to patient activity; (b) providing a maximum activity value; (c) calibrating the control function so that the provided minimum activity value relates to the selected minimum pacing rate and the provided maximum activity value relates to the selected maximum pacing rate; (d) selecting the pacing rate in response to a measure of the physiological parameter using the calibrated control function; (e) obtaining a first activity value based on a first time measure of the physiological parameter corresponding to the patient'"'"'s average activity over a first time period; (f) adjusting the maximum activity value in response to the first activity value being greater than the maximum activity value, so that the adjusted maximum activity value is the lesser of the first activity value and the preexisting maximum activity value times a first constant, the first constant being selected from between 1.03 and 1.12; and (g) maintaining the maximum activity value unadjusted if it is greater than the first activity value. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54)
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55. In a pacemaker having a control relation between the pacing rate (FC) and a monitored minute volume physiological parameter (VE) measured over a breathing cycle of the patient indicative of patient activity, the control relation having coefficients defining a programmed minimum rate (FC low) and a programmed maximum rate (FC max), apparatus for adjusting a control relation, comprising:
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means for receiving an initial minimum parameter VE low based on a mean minute volume value taken over a plurality of breathing cycles of the patient at rest, the plurality being selected from between 4 and 16; means for receiving an initial maximum parameter VE max; first means for calculating automatically a value VE low and a value VE max in response to subsequently obtained measures of the minute volume corresponding to patient maximum and minimum activity levels, respectively; and means for adjusting the control relation to intersect two pairs of values (FC low, VE low) and (FC max, VE max) to correspond to the real needs of the patient. - View Dependent Claims (56, 57, 58, 59, 60)
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Specification