Implantable system for flow measurement including charge amplifier
First Claim
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1. A flow measurement system comprising:
- a medical device;
a lead adapted for implantation within a patient;
a flow measurement means, mounted on the lead, for detecting a flow parameter of ionic media at a detecting position in a selected detecting area when the lead is inserted into the patient;
a capsule, positioned on the lead proximate to the flow measurement means, the flow measurement means comprising at least first and second electrodes, the capsule positioned on the lead proximate to at least the first electrode;
electrical circuitry, housed within the capsule and operatively connected to the first electrode, for receiving and processing flow signals from the flow measurement means; and
a plurality of electrical conductors contained in said lead, at least one conductor having a distal end operatively connected to the electrical circuitry and having a proximal end operatively connected to the medical device; and
wherein the electrical circuitry comprises a charge amplifier, having one or more pluralities of feedback capacitors, feedback resistors, and input resistors, each of the pluralities connected to the charge amplifier via switches, the charge amplifier being configured to digitize the flow signals from the flow measurement means, said digitized flow signals being transmitted through the at least one conductor from the capsule to the medical device, andwherein the medical device comprises a control circuit operatively connected to the charge amplifier via one or more of the lead conductors, the control circuit adapted to periodically determine source capacitance of the charge amplifier and adapted to trigger one or more of the switches to adjust one or more of gain, low cutoff frequency, and high cutoff frequency of the amplifier to correspond with the determined source capacitance.
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Abstract
An implantable medical device lead having a flow measurement sensor mounted thereon is provided with a capsule mounted proximate to the sensor. The capsule is used to house electrical circuitry corresponding to the sensor in order to prevent impedance on conductors of the lead, which gradually decreases over chronic periods, from directly affecting signal transmission between the sensor and the electrical circuitry. The electrical circuitry includes a charge amplifier used for processing signals from the sensor. In some cases, the amplifier can be initially calibrated and periodically tuned so as to have consistent functioning with the sensor over chronic periods.
13 Citations
11 Claims
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1. A flow measurement system comprising:
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a medical device; a lead adapted for implantation within a patient; a flow measurement means, mounted on the lead, for detecting a flow parameter of ionic media at a detecting position in a selected detecting area when the lead is inserted into the patient; a capsule, positioned on the lead proximate to the flow measurement means, the flow measurement means comprising at least first and second electrodes, the capsule positioned on the lead proximate to at least the first electrode; electrical circuitry, housed within the capsule and operatively connected to the first electrode, for receiving and processing flow signals from the flow measurement means; and a plurality of electrical conductors contained in said lead, at least one conductor having a distal end operatively connected to the electrical circuitry and having a proximal end operatively connected to the medical device; and wherein the electrical circuitry comprises a charge amplifier, having one or more pluralities of feedback capacitors, feedback resistors, and input resistors, each of the pluralities connected to the charge amplifier via switches, the charge amplifier being configured to digitize the flow signals from the flow measurement means, said digitized flow signals being transmitted through the at least one conductor from the capsule to the medical device, and wherein the medical device comprises a control circuit operatively connected to the charge amplifier via one or more of the lead conductors, the control circuit adapted to periodically determine source capacitance of the charge amplifier and adapted to trigger one or more of the switches to adjust one or more of gain, low cutoff frequency, and high cutoff frequency of the amplifier to correspond with the determined source capacitance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A flow measurement system comprising:
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a medical device; a lead adapted for implantation within a patient; a flow measurement means, mounted on an exterior surface of the lead, for detecting a flow parameter of ionic media at a detecting position in contact with the exterior surface of the lead when the lead is inserted into the patient; a capsule, positioned on the lead proximate to the flow measurement means, the flow measurement means comprising at least first and second electrodes, the capsule positioned on the lead proximate to at least the first electrode; electrical circuitry, housed within the capsule and operatively connected to the first electrode, for receiving and processing flow signals from the flow measurement means; and a plurality of electrical conductors contained in said lead, at least one conductor having a distal end operatively connected to the electrical circuitry and having a proximal end operatively connected to the medical device; and wherein the electrical circuitry comprises a charge amplifier that is configured to digitize the flow signals from the flow measurement means, said digitized flow signals being transmitted through the at least one conductor from the capsule to the medical device.
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11. A flow measurement system comprising:
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a medical device; a lead adapted for implantation within a patient; a flow measurement means, mounted on the lead, for detecting a flow parameter of ionic media at a detecting position in a selected detecting area when the lead is inserted into the patient; a capsule, positioned on the lead proximate to the flow measurement means, the flow measurement means comprising at least first and second electrodes, the capsule positioned on the lead proximate to at least the first electrode; electrical circuitry, housed within the capsule and operatively connected to the first electrode, for receiving and processing flow signals from the flow measurement means; and a plurality of electrical conductors contained in said lead, at least one conductor having a distal end operatively connected to the electrical circuitry and having a proximal end operatively connected to the medical device; and wherein the electrical circuitry comprises a charge amplifier that is configured to digitize the flow signals from the flow measurement means, said digitized flow signals being transmitted through the at least one conductor from the capsule to the medical device, and wherein the medical device comprises a control circuit operatively connected to the charge amplifier via one or more of the lead conductors, the control circuit adapted to periodically determine source capacitance of the charge amplifier and adapted to adjust one or more of gain, low cutoff frequency, and high cutoff frequency of the amplifier to correspond with the determined source capacitance.
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Specification