METHOD AND APPARATUS FOR DISCONNECTING THE TIP ELECTRODE DURING MRI
First Claim
1. An electrode isolation device for electrically isolating an electrode of an implantable lead in the presence of a magnetic field, the implantable lead including a lead conductor configured to connect the electrode to a pulse generator via first and second conductive paths, the electrode isolation device comprising:
- a first switch coupled between the pulse generator and the electrode along the first conductive path, the first switch including an open state in the presence of the magnetic field that electrically disconnects the first conductive path between the pulse generator and the electrode, the first switch further including a closed state in the absence of the MRI magnetic field that electrically connects the first conductive path between the pulse generator and the electrode; and
a second switch coupled between the pulse generator and the electrode along the second conductive path, the second switch including an open state that electrically disconnects the first conductive path between the pulse generator and the electrode, the second switch further including a closed state that electrically connects the second conductive path between the pulse generator and the electrode when a voltage applied across the second switch exceeds a threshold voltage.
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Abstract
A medical device includes a pulse generator, a lead, and an electrode. The lead includes an electrode and a lead conductor connecting the pulse generator with the electrode via first and second conductive paths. The medical device includes first and second switches. The first switch is disposed along the first conductive path and includes an open state in the presence of a magnetic field and a closed state in the absence of the magnetic field. The second switch is disposed along the second conductive path and includes an open state when a voltage applied across the second switch is at or below a threshold voltage and a closed state when the voltage applied across the second switch exceeds a threshold voltage.
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Citations
20 Claims
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1. An electrode isolation device for electrically isolating an electrode of an implantable lead in the presence of a magnetic field, the implantable lead including a lead conductor configured to connect the electrode to a pulse generator via first and second conductive paths, the electrode isolation device comprising:
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a first switch coupled between the pulse generator and the electrode along the first conductive path, the first switch including an open state in the presence of the magnetic field that electrically disconnects the first conductive path between the pulse generator and the electrode, the first switch further including a closed state in the absence of the MRI magnetic field that electrically connects the first conductive path between the pulse generator and the electrode; and a second switch coupled between the pulse generator and the electrode along the second conductive path, the second switch including an open state that electrically disconnects the first conductive path between the pulse generator and the electrode, the second switch further including a closed state that electrically connects the second conductive path between the pulse generator and the electrode when a voltage applied across the second switch exceeds a threshold voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for selectively connecting a pulse generator and an electrode, the method comprising:
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controlling a state of a first switch coupled along a first conductive path between the pulse generator and the electrode such that, in the absence of a magnetic field, the first switch is closed to electrically connect the pulse generator and the electrode via the first conductive path, and in the presence of the magnetic field, the first switch is open to electrically disconnect the first conductive path between the pulse generator and the electrode; and controlling a state of a second switch coupled along a second conductive path between the pulse generator and the electrode such that the second switch is open to electrically disconnect the second conductive path between the pulse generator and the electrode when a voltage applied across the second switch is less than or equal to a threshold voltage, and second switch is closed to electrically connect the pulse generator and the electrode via the second conductive path when the voltage applied across the second switch is greater than the threshold voltage. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for delivering therapy from a pulse generator to an electrode, the pulse generator connected to the electrode via first and second conductive paths, comprising:
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delivering one or more therapy signals at a first voltage level when the pulse generator is operating in a normal mode in the absence of a magnetic field, the one or more therapy signals at the first voltage level reaching the electrode via the first conductive path; and delivering one or more therapy signals from the pulse generator at a second voltage level when the pulse generator is operating in an MRI mode in the presence of the magnetic field, the second voltage level greater than the first voltage level, the one or more therapy signals from the pulse generator at the second voltage level reaching the electrode via the second conductive path. - View Dependent Claims (19, 20)
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Specification