Hemodynamically rate responsive pacemaker and method of automatically adjusting the escape and A-V intervals
First Claim
1. In a dual chamber pacemaker, a system for optimizing cardiac output of a patient'"'"'s heart, the pacemaker having a pulse generator for generating atrial and ventricular stimulation pulses and timing means for defining a pacing cycle having a stimulation rate and a A-V time interval between the atrial and the ventricular stimulation pulses, the stimulation rate and the A-V interval being adjustable in discrete steps, the system comprising:
- a physiological sensor for sensing, during at least one cardiac cycle, a physiological parameter indicative of the cardiac output of the patient'"'"'s heart;
means for determining an optimal stimulation rate corresponding to a maximum value of the physiological parameter;
means for adjusting the stimulation rate to a suboptimal stimulation rate, the suboptimal stimulation rate being at least one discrete step below the optimal stimulation rate;
means for determining an optimal A-V time interval, the optimal A-V time interval corresponding to a maximum value of the physiological parameter while the stimulation rate equals the suboptimal stimulation rate; and
means for adjusting the A-V time interval to the optimal A-V time interval while the stimulation rate is at the suboptimal stimulation rate.
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Accused Products
Abstract
In a rate responsive pacemaker, a physiological sensor is used to sense the physiological needs of the patient'"'"'s heart and to control both the pacing rate and the A-V interval accordingly. A first adjustment means triggers the timing circuitry to adjust the stimulation rate to a slightly sub-optimal value of cardiac output. A second adjustment means adjusts the A-V interval until hemodynamics are optimized according to the physiological sensor. The improvement in hemodynamics due to the A-V adjustment allows a further decrease in the stimulation rate by the first adjustment means, thereby conserving the limited battery supply.
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Citations
26 Claims
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1. In a dual chamber pacemaker, a system for optimizing cardiac output of a patient'"'"'s heart, the pacemaker having a pulse generator for generating atrial and ventricular stimulation pulses and timing means for defining a pacing cycle having a stimulation rate and a A-V time interval between the atrial and the ventricular stimulation pulses, the stimulation rate and the A-V interval being adjustable in discrete steps, the system comprising:
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a physiological sensor for sensing, during at least one cardiac cycle, a physiological parameter indicative of the cardiac output of the patient'"'"'s heart; means for determining an optimal stimulation rate corresponding to a maximum value of the physiological parameter; means for adjusting the stimulation rate to a suboptimal stimulation rate, the suboptimal stimulation rate being at least one discrete step below the optimal stimulation rate; means for determining an optimal A-V time interval, the optimal A-V time interval corresponding to a maximum value of the physiological parameter while the stimulation rate equals the suboptimal stimulation rate; and means for adjusting the A-V time interval to the optimal A-V time interval while the stimulation rate is at the suboptimal stimulation rate. - View Dependent Claims (2, 3)
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4. In a dual chamber pacemaker, a system for optimizing cardiac output of a patient'"'"'s heart, the pacemaker having a pulse generator for generating atrial and ventricular stimulation pulses and timing means for defining a pacing cycle having a stimulation rate and a A-V time interval between the atrial and the ventricular stimulation pulses, the stimulation rate and the A-V interval being adjustable in discrete steps, the system comprising:
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a physiological sensor for sensing, during at least one cardiac cycle, a physiological parameter indicative of the cardiac output of the patient'"'"'s heart; means for adjusting the stimulation rate to an optimal stimulation rate, the optimal stimulation rate corresponding to a maximum value of the physiological parameter; means for decreasing the stimulation rate from the optimal stimulation rate by at least one discrete step to obtain a suboptimal stimulation rate; and means for adjusting the A-V time interval to an optimal A-V time interval while the stimulation rate is at the suboptimal stimulation rate, the optimal A-V time interval corresponding to a maximum value of the physiological parameter while stimulating at the suboptimal stimulation rate. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12)
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13. In a rate responsive pacemaker, a system for adjusting the stimulation rate of the heart of a patient with congestive heart failure, the pacemaker having a pulse generator for generating stimulation pulses to the patient'"'"'s heart, and timing means for generating a variable stimulation rate, the system comprising:
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a physiological sensor for sensing a physiological parameter having a value indicative of the physiological needs of the patient'"'"'s heart, wherein a decrease in the value of the physiological parameter indicates a need for an increase in heart rate; means for adjusting the stimulation rate in response to a sensed change in the physiological parameter; a first detection means for detecting a decrease in the value of the physiological parameter as a result of an increase in the stimulation rate, whereby congestive heart failure is detected; and means for decreasing the stimulation rate in response to the first detection means. - View Dependent Claims (14, 15, 16)
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17. In a dual chamber pacemaker, a method for optimizing cardiac output of a patient'"'"'s heart, the pacemaker having a pulse generator for generating atrial and ventricular stimulation pulses and timing means for defining a pacing cycle having a stimulation rate and a A-V time interval between the atrial and the ventricular stimulation pulses, the stimulation rate and the A-V interval being adjustable in discrete steps, the method comprising the steps of:
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a) sensing, during at least one cardiac cycle, a physiological parameter indicative of the cardiac output of the patient'"'"'s heart; b) determining an optimal stimulation rate corresponding to a maximum value of the physiological parameter; c) adjusting the stimulation rate to a suboptimal stimulation rate, the suboptimal stimulation rate being at least one discrete step below the optimal stimulation rate; d) determining an optimal A-V time interval, the optimal A-V time interval corresponding to a maximum value of the physiological parameter while the stimulation rate equals the suboptimal stimulation rate; and e) adjusting the A-V time interval to the optimal A-V time interval while the stimulation rate is at the suboptimal stimulation rate. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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24. In a dual chamber pacemaker, a method for optimizing cardiac output of a patient'"'"'s heart, the pacemaker having a pulse generator for generating atrial and ventricular stimulation pulses and timing means for defining a pacing cycle having a stimulation rate and a A-V time interval between the atrial and the ventricular stimulation pulses, the stimulation rate and the A-V interval being adjustable in discrete steps, the method comprising the steps of:
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sensing, during at least one cardiac cycle, a physiological parameter indicative of the cardiac output of the patient'"'"'s heart; adjusting the stimulation rate to an optimal stimulation rate, the optimal stimulation rate corresponding to a maximum value of the physiological parameter; decreasing the stimulation rate from the optimal stimulation rate by at least one discrete step to obtain a suboptimal stimulation rate; and adjusting the A-V time interval to an optimal A-V time interval while the stimulation rate is at the suboptimal stimulation rate, the optimal A-V time interval corresponding to a maximum value of the physiological parameter.
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25. In a rate responsive pacemaker, a method for adjusting the stimulation rate of the heart of a patient with congestive heart failure, the pacemaker having a pulse generator for generating stimulation pulses to the patient'"'"'s heart, and timing means for generating a variable stimulation rate, the method comprising the steps of:
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sensing a value of a physiological parameter indicative of the physiological needs of the patient'"'"'s heart, wherein a decrease in the value of the physiological parameter indicates a need for an increase in heart rate; adjusting the stimulation rate in response to a sensed change in the physiological parameter; detecting a decrease in the value of the physiological parameter as a result of an increase in the stimulation rate, whereby congestive heart failure is detected; and decreasing the stimulation rate in response to the detected decrease in the value of the physiological parameter as a result of the increase in the stimulation rate. - View Dependent Claims (26)
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Specification