Lead impedance scanning system for pacemakers
First Claim
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1. A lead impedance scanning system for an implantable stimulation device for stimulating body tissue, the body tissue having an electrical impedance, said scanning system comprising:
- pulse generator means for generating stimulation pulses to the body tissue during a stimulation time interval;
sensing means for sensing, during a sensing time interval, electrical signals generated by the body tissue;
an implantable lead having an electrical impedance, said lead being implantable in the body tissue and coupled to said pulse generator means for delivering said stimulation pulses and to said sensing means for receiving said electrical signals; and
detection means for detecting, during said simulation time interval and said sensing time interval, changes in combined impedance of said lead and of the body tissue at a point of contact of said lead with the body tissue.
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Abstract
A pacemaker lead analyzer for measuring impedance during standard operation of an implanted pacemaker. The analyzer makes separate measurements of lead impedance during each heart signal and each pacing pulse. A moving average of measured parameters is maintained and recurring deviations from the norms are noted in separate event counters for subsequent analysis of the noted events as possible indications of impending failure of an implanted lead.
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Citations
32 Claims
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1. A lead impedance scanning system for an implantable stimulation device for stimulating body tissue, the body tissue having an electrical impedance, said scanning system comprising:
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pulse generator means for generating stimulation pulses to the body tissue during a stimulation time interval; sensing means for sensing, during a sensing time interval, electrical signals generated by the body tissue; an implantable lead having an electrical impedance, said lead being implantable in the body tissue and coupled to said pulse generator means for delivering said stimulation pulses and to said sensing means for receiving said electrical signals; and detection means for detecting, during said simulation time interval and said sensing time interval, changes in combined impedance of said lead and of the body tissue at a point of contact of said lead with the body tissue. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An apparatus for measuring lead impedance of an implantable stimulation device for stimulating body tissue which has an electrical impedance, the apparatus comprising:
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means for measuring a stimulation pulse voltage over a single pulse; an impedance lead having an electrical impedance, said lead being implantable in the body tissue and coupled to said pulse generator means for delivering said stimulating pulse; and impedance discriminating means for determining a corresponding lead impedance measurement derived from said stimulation pulse voltage, said lead impedance measurement being the combined impedances of said lead and the body tissue. - View Dependent Claims (15, 16)
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17. A method of detecting the existence of a defective lead, said lead implanted in the body tissue and coupled to an implantable stimulation device which stimulates body tissue, said lead and the body tissue having an electrical impedance, comprising the steps of:
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generating stimulation pulses to the body tissue during a stimulation time interval; sensing electrical signals generated by the body tissue during a sensing time interval; and detecting, during said stimulation time interval and said sensing time interval, changes in the combined impedances of said lead and of the body tissue at the point of contact of said lead with the body tissue. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A method of measuring the combined impedance of an implantable lead coupled to an implantable stimulation device and body tissue at the point of contact of said lead with said body tissue, comprising the steps of:
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delivering stimulating pulses from said implantable stimulation device to said body tissue through said implantable lead; measuring a single stimulation pulse voltage; and determining a corresponding lead impedance measurement derived from said single stimulation pulse voltage. - View Dependent Claims (31, 32)
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Specification