Implantable medical leads, systems, and related methods for creating a high impedance within a conduction path in the presence of a magnetic field of a given strength
First Claim
1. A method of creating a high impedance within a conduction path of an implantable medical lead, comprising:
- providing a first magnetically responsive actuator that when in a presence of a magnetic field of an MRI scanner moves from a first start position toward a first stop position and reaches the first stop position when the magnetic field is not oriented normal to a direction of movement of the first actuator;
providing a second magnetically responsive actuator that when in the presence of the magnetic field moves from a second start position toward a second stop position and reaches the second stop position when the magnetic field is not oriented parallel to a direction of movement of the second actuator; and
providing at least one switch in series with the conduction path, the at least one switch being coupled to both the first actuator and the second actuator, wherein the at least one switch resides in a closed state and achieves an open state to create the high impedance when the first actuator reaches the first stop position and/or when the second actuator reaches the second stop position.
1 Assignment
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Accused Products
Abstract
Implantable medical systems include implantable medical leads that have magnetic orientation-independent magnetically actuated switches that are placed in the conduction path to the electrode of the lead. Thus, regardless of the orientation of a substantial magnetic field like that from an MRI machine to the lead and switch within the lead, the switch opens when in the presence of that substantial magnetic field. The switch may be placed in close proximity to the electrode such that the opening of the switch disconnects the electrode from the majority of the conduction path which thereby produces a high impedance for RF current and reduces the amount of heating that may occur at the electrode when in the presence of substantial levels of RF electromagnetic energy as may occur within an MRI machine.
16 Citations
23 Claims
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1. A method of creating a high impedance within a conduction path of an implantable medical lead, comprising:
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providing a first magnetically responsive actuator that when in a presence of a magnetic field of an MRI scanner moves from a first start position toward a first stop position and reaches the first stop position when the magnetic field is not oriented normal to a direction of movement of the first actuator; providing a second magnetically responsive actuator that when in the presence of the magnetic field moves from a second start position toward a second stop position and reaches the second stop position when the magnetic field is not oriented parallel to a direction of movement of the second actuator; and providing at least one switch in series with the conduction path, the at least one switch being coupled to both the first actuator and the second actuator, wherein the at least one switch resides in a closed state and achieves an open state to create the high impedance when the first actuator reaches the first stop position and/or when the second actuator reaches the second stop position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An implantable medical lead, comprising:
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a lead body; at least one conductor surrounded by the lead body; at least one electrode coupled to the lead body on the distal end of the lead body; a first magnetically responsive actuator within the lead body that when in a presence of a magnetic field of an MRI scanner moves from a first start position toward a first stop position and reaches the first stop position when the magnetic field is not oriented normal to a direction of movement of the first actuator; a second magnetically responsive actuator within the lead body that when in the presence of the magnetic field moves from a second start position toward a second stop position and reaches the second stop position when the magnetic field is not oriented parallel to a direction of movement of the second actuator; and at least one switch within the lead body that is coupled to the first and second switches and that is in series between the conductor and the electrode on the distal end of the lead body, the at least one switch residing in a closed state and achieving an open state to create a high impedance between the conductor and the electrode on the distal end of the lead body when the first actuator reaches the first stop position and/or when the second actuator reaches the second stop position. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A medical system, comprising:
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a pulse generator; and an implantable medical lead that comprises; a lead body; at least one conductor surrounded by the lead body, the at least one conductor being electrically coupled to the pulse generator; at least one electrode coupled to the lead body on the distal end of the lead body; a first magnetically responsive actuator within the lead body that when in a presence of a magnetic field of an MRI scanner moves from a first start position toward a first stop position and reaches the first stop position when not oriented normal to a direction of movement of the first actuator; a second magnetically responsive actuator within the lead body that when in the presence of a magnetic field moves from a second start position toward a second stop position and reaches the second stop position when not oriented parallel to a direction of movement of the second actuator; and at least one switch within the lead body that is coupled to the first and second actuators and that is in series between the conductor and the electrode on the distal end of the lead body, the at least one switch residing in a closed state and achieving an open state to create a high impedance between the conductor and the electrode on the distal end of the lead body when the first actuator reaches the first stop position and/or when the second actuator reaches the second stop position. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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Specification