Impedance monitoring for detecting pulmonary edema and thoracic congestion
First Claim
1. An implantable medical device comprising:
- a housing for the implantable device sized for implantation in a chest region of a patient and comprising a housing electrode;
a left ventricular lead port into which a proximal end of a lead is connectable, the lead having first and second conductors that are insulated from one another and that extend from the proximal end of the lead to corresponding first and second electrodes positioned near a distal end of the lead; and
an electrical impedance measurement circuit electrically connected to the left ventricular lead port and to the housing electrode, the circuit to inject current between the first lead electrode and the housing electrode, and to measure a voltage potential between the second lead electrode and the housing electrode, the voltage potential created by the current injection.
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Accused Products
Abstract
An implantable medical device includes a housing for the implantable device that is sized for implantation in a chest region of a patient and includes a housing electrode. A left ventricular lead port is connectable to a proximal end of a lead having first and second insulated conductors that extend from the proximal end of the lead to corresponding first and second electrodes near a distal end of the lead. An electrical impedance measurement circuit is electrically connected to the left ventricular lead port and the housing electrode. The circuit may inject current between the first lead electrode and the housing electrode, and measure a voltage potential, created by the current injection, between the second lead electrode and the housing electrode. The ratio of the measured voltage to injected current may be used for assessing pulmonary edema. The lead electrodes may be located in a left ventricular coronary vein.
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Citations
28 Claims
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1. An implantable medical device comprising:
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a housing for the implantable device sized for implantation in a chest region of a patient and comprising a housing electrode;
a left ventricular lead port into which a proximal end of a lead is connectable, the lead having first and second conductors that are insulated from one another and that extend from the proximal end of the lead to corresponding first and second electrodes positioned near a distal end of the lead; and
an electrical impedance measurement circuit electrically connected to the left ventricular lead port and to the housing electrode, the circuit to inject current between the first lead electrode and the housing electrode, and to measure a voltage potential between the second lead electrode and the housing electrode, the voltage potential created by the current injection. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An implantable medical device, comprising:
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a housing for the implantable device sized for implantation in a chest region of a patient and comprising a housing electrode;
a left ventricular lead port into which a proximal end of a first lead is connectable, the first lead having first and second conductors that are insulated from one another and that extend from the proximal end of the first lead to corresponding first and second electrodes positioned near a distal end of the first lead;
a right atrial lead port into which a proximal end of a second lead is connectable, the second lead having first and second conductors that are insulated from one another and that extend from the proximal end of the second lead to corresponding third and fourth electrodes positioned near a distal end of the second lead; and
an electrical impedance measurement circuit electrically connected to the left ventricular lead port, the housing electrode, and the right atrial lead port, the circuit to inject a first current between the first electrode and the housing electrode, and to measure a first voltage potential between the second electrode and the housing electrode, the first voltage potential created by the first current injection, the circuit to further inject a second current between the third electrode and the housing electrode, and to measure a second voltage potential between the fourth electrode and the housing electrode, the second voltage potential created by the second current injection. - View Dependent Claims (16, 17, 18, 19)
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20. A method of monitoring pulmonary edema in a human being, the method comprising:
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injecting an electrical current between a first electrode located in a coronary vein of a left ventricle and a housing of a medical device implanted in a chest region; and
measuring a voltage potential between a second electrode located in the coronary vein of the left ventricle and the medical device housing. - View Dependent Claims (21, 22)
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23. A method of monitoring pulmonary edema in a human being, the method comprising:
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injecting a first electrical current between a first electrode located in a coronary vein of a left ventricle and a housing of a medical device implanted in a chest region;
measuring a first voltage potential between a second electrode located in the coronary vein of the left ventricle and the medical device housing, the first voltage potential created by the first current injection;
injecting a second electrical current between a third electrode located in a right atrium and the medical device housing; and
measuring a second voltage potential between a fourth electrode located in the right atrium and the medical device housing, the second voltage potential created by the second current injection. - View Dependent Claims (24, 25)
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- 26. A method of measuring electrical impedance in a human being, the method comprising measuring an electrical impedance at a moment of end-systole and end-expiration, the electrical impedance measured between a housing of a medical device implanted in a chest region and electrodes located in a coronary vein of a left ventricle.
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28. A method of determining electrical impedance in a human being, the method comprising:
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measuring an electrical impedance between a housing of a medical device implanted in a chest region and electrodes located in a coronary vein of a left ventricle;
determining a degree of pulmonary edema in the human being, the determination based on the measured electrical impedance;
receiving orientation information from a posture sensor, the orientation information indicating a position of the human being; and
adjusting a relationship between the electrical impedance and the degree of pulmonary edema based on the orientation information.
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Specification