Minute volume rate-responsive pacemaker employing impedance sensing on a unipolar lead
First Claim
1. A rate-responsive pacemaker comprising:
- pulsing means for providing pacing current pulses at a controlled rate;
a unipolar lead coupled to said pulsing means and having an electrode adapted to couple said pulsing means to a patient'"'"'s heart for delivering said pacing current pulses to said heart;
means for periodically applying a measuring current between said lead and a reference point in said pacemaker, said measuring current having frequency components in a range extending from approximately 10 kilohertz to approximately 1000 megahertz;
means operative during the application of said measuring current between said lead and said reference point for measuring the spatial impedance between said lead and said reference point as a function of the patient'"'"'s pleural pressure;
means responsive to said measuring means for determining the patient'"'"'s minute volume; and
means coupled to said pulsing means for changing said controlled rate in accordance with the patient'"'"'s minute volume.
2 Assignments
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Accused Products
Abstract
A rate-responsive pacemaker employing a rate control parameter of respiratory minute volume, derived over a unipolar lead. The pacemaker performs the minute volume measurement by periodically applying a measuring current between the lead and a reference point on the pacemaker case. This measuring current has frequency components in a range from approximately 10 kilohertz to 1000 megahertz. Application of this measuring current allows the pacemaker to detect the voltage which arises from the applied current and, from the detected voltage, to measure the patient'"'"'s spatial impedance. Spatial impedance and minute volume vary as a function of the patient'"'"'s pleural pressure. The pacemaker derives minute volume and rate-responsive pacing rate from the spatial impedance measurement.
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Citations
44 Claims
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1. A rate-responsive pacemaker comprising:
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pulsing means for providing pacing current pulses at a controlled rate; a unipolar lead coupled to said pulsing means and having an electrode adapted to couple said pulsing means to a patient'"'"'s heart for delivering said pacing current pulses to said heart; means for periodically applying a measuring current between said lead and a reference point in said pacemaker, said measuring current having frequency components in a range extending from approximately 10 kilohertz to approximately 1000 megahertz; means operative during the application of said measuring current between said lead and said reference point for measuring the spatial impedance between said lead and said reference point as a function of the patient'"'"'s pleural pressure; means responsive to said measuring means for determining the patient'"'"'s minute volume; and means coupled to said pulsing means for changing said controlled rate in accordance with the patient'"'"'s minute volume. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A rate-responsive pacemaker comprising:
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pulsing means for providing pacing pulses at a controlled rate; a unipolar lead coupled to said pulsing means and having an electrode adapated to couple said pulsing means to a patient'"'"'s heart; means for periodically introducing a measuring current between said lead and a reference point and measuring the voltage across said lead and said reference point to derive a spatial impedance signal; and means coupled to said pulsing means for adjusting said controlled rate as a function of said spatial impedance signal. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. A method for pacing a patient'"'"'s heart at a controlled pacing rate in accordance with the patient'"'"'s repiration minute volume signal, comprising the steps of:
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providing an implantable pacemaker and a unipolar lead having an electrode for generating and coupling pacing stimulation pulses to the patient'"'"'s heart; periodically applying a measuring current between said lead and a reference point in said pacemaker, said measuring current having frequency components in a range of from approximately 10 kilohertz to approximately 1000 megahertz; measuring the spatial impedance between said lead and said reference point in response to said application of measuring current between the lead and the reference point while the spatial impedance varies as a function of the patient'"'"'s pleural pressure; determining the patient'"'"'s respiratory minute volume based on said spatial impedance measurement; and changing the controlled pacing rate in accordance with the patient'"'"'s determined minute volume. - View Dependent Claims (39, 40, 41, 42, 43, 44)
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Specification