Patent application number | Description | Published |
20090149906 | METHOD AND APPARATUS FOR DISCONNECTING THE TIP ELECTRODE DURING MRI - 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 includes a non-conductive state in the presence of a magnetic field, the non-conductive state preventing formation of the first conductive path between the pulse generator and the electrode. The second switch includes a non-conductive state that prevents formation of the second conductive path between the pulse generator and the electrode. The first switch in the non-conductive state and the second switch in the non-conductive state electrically shields the electrode from electromagnetic radiation and induced voltages during a magnetic resonance imaging procedure. | 06-11-2009 |
20090149909 | SELECTIVELY CONNECTING THE TIP ELECTRODE DURING THERAPY FOR MRI SHIELDING - A medical device includes a pulse generator and an electrode configured to contact tissue in a body vessel. The medical device includes a lead that includes a lead connector. The lead connector connects a pulse generator with an electrode via a conductive path. An electrode switch is electrically connected between the lead conductor and the electrode. The electrode switch includes an open state preventing the conductive path between the lead and the electrode. The electrode switch includes a closed state establishing the conductive path between the lead and the electrode when a voltage is applied across the electrode switch that exceeds a threshold voltage. The electrode switch in the open state electrically shields the electrode from electromagnetic radiation and induced voltages during magnetic resonance imaging. | 06-11-2009 |
20090149920 | LEADS WITH HIGH SURFACE RESISTANCE - Implantable medical leads having resistance characteristics adapted to dissipate radio frequency (RF) electromagnetic energy during medical procedures such as magnetic resonance imaging (MRI) are disclosed. An illustrative medical device includes a lead having an inner electrical conductor operatively coupled to an electrode and a pulse generator, and one or more outer resistive shields that radially surround the inner conductor and dissipate RF energy into the surrounding body tissue along the length of the lead. | 06-11-2009 |
20090149933 | IMPLANTABLE LEAD HAVING A VARIABLE COIL CONDUCTOR PITCH - Systems and methods for shielding implantable leads from magnetic fields during medical procedures such as magnetic resonance imaging (MRI) are described. In various embodiments, the lead includes an inner conductor that is helically shaped and radially surrounded, at least in part, by one or more outer shielding conductors. The pitch of the inner conductor, and in some cases also the outer conductor, can be varied (e.g., continuously or at certain points) along the length of the lead, forming a plurality of high impedance points along the length of the lead which result in the dissipation of electromagnetic energy at an interrogation frequency of a magnetic resonance imaging device (e.g., 64 MHz, 128 MHz, or the like). In some embodiments, the variance in the pitch of the inner conductor follows a sinusoidal function, a modified square-wave function, or some other repeating pattern. | 06-11-2009 |
20090149934 | IMPLANTABLE LEAD WITH SHIELDING - Medical device leads with magnetic shielding and methods of shielding medical device leads from magnetic fields during medical procedures such as magnetic resonance imaging (MRI) are described. An illustrative implantable medical device includes a lead including a lead conductor having a length and a helically coiled ribbon shield radially surrounding the lead conductor along at least a portion of the length of the lead. The ribbon shield can include one or more inner ribbon conductors and/or one or more outer ribbon conductors. The outer ribbon conductor can have a variable width (e.g., a necked-down configuration, an arrowhead configuration, or an undulating configuration) along the length of the lead. In some cases, the helically coiled ribbon has a variable pitch along the length of the lead that may be the same as or different from that of the lead conductor pitch. | 06-11-2009 |
20090204171 | MRI SHIELDING IN ELECTRODES USING AC PACING - A medical device includes a pulse generator, an electrode configured to contact tissue in a coronary vessel, a lead comprising a lead conductor, the lead conductor connecting the pulse generator with the electrode, and a filter circuit electrically connected in series between the lead conductor and the electrode. The filter circuit may include a band pass filter that attenuates signals having a frequency other than a natural resonance frequency (e.g. MRI device signals), and the pulse generator may transmit therapy signals to the electrode as a sinusoidal voltage wave at the natural resonance frequency. The filter circuit may include a diode that rectifies the sinusoidal voltage wave before the rectified sinusoidal voltage wave passes to the electrode. In some embodiments, therapy signals may be provided to the electrode through the band pass filter over a natural resonance frequency range. | 08-13-2009 |
20090204182 | MAGNETIC CORE FLUX CANCELING OF FERRITES IN MRI - A magnetic core flux canceling device according to embodiments of the present invention includes a magnetic field sensor adapted for placement at a ferrite material core in an implantable medical device, the magnetic field sensor adapted to transmit a signal corresponding to a magnitude of a first magnetic field. Such a device may also include a coil disposed around the ferrite material core and a driver circuit configured to receive the signal and to vary a voltage applied across the coil based on the signal, the voltage applied across the coil creating a second magnetic field at least partially in a direction opposite the first magnetic field. According to some embodiments of the present invention, multiple coils may be used to cancel magnetic fields in multiple directions. A voltage applied across the coil varies in magnitude and/or direction to cancel or weaken an MRI-related magnetic field. | 08-13-2009 |
20090210025 | MODEL REFERENCE IDENTIFICATION AND CANCELLATION OF MAGNETICALLY-INDUCED VOLTAGES IN A GRADIENT MAGNETIC FIELD - Systems and methods of dynamically controlling an implanted medical device located within a patient's body in the presence of a gradient magnetic field or other external interference are disclosed. The system can include a reference model of the implanted medical device and of body tissue within the patient's body in the absence of a gradient magnetic field, and a control unit configured to dynamically control voltages or currents applied to a lead of the implanted medical device based on predicted parameters determined by the reference model. | 08-20-2009 |
20110087302 | MRI COMPATIBLE MEDICAL DEVICE LEAD INCLUDING TRANSMISSION LINE NOTCH FILTERS - A medical device lead includes a conductor and one or more band stop filters. The conductor extends through a lead body and includes a proximal end and a distal end. The one or more band stop filters each have a first end and a second end and include a conductive coil. At least one of the first end and second end of each band stop filter is coupled to the conductor. A length of each band stop filter is such that, at magnetic resonance imaging (MRI) frequencies, the band stop filter phase shifts an MRI-induced signal on the conductor by 180° to attenuate the MRI-induced signal on the conductor. | 04-14-2011 |
20110093054 | MRI COMPATIBLE TACHYCARDIA LEAD - A medical device lead includes a proximal connector configured to couple the lead to a pulse generator, an insulative lead body extending distally from the proximal connector, and a conductor assembly extending distally from the proximal connector within the lead body. The conductor assembly includes a conductor having a proximal end electrically coupled to the connector and a distal end electrically coupled to a defibrillation coil. A first portion of the defibrillation coil is exposed at an outer surface of the medical device lead and a second portion of the defibrillation coil is insulated at the outer surface of the medical device lead. | 04-21-2011 |
20110159371 | IMPLANTABLE MEDICAL DEVICE INCLUDING EDDY CURRENT REDUCING BATTERY - An implantable device, such as a pacer, defibrillator, or other cardiac rhythm management device, can include one or more MRI Safe components. In an example, the implantable device includes a battery including a first electrode and a second electrode separate from the first electrode. The second electrode includes a first surface and a second surface. The second electrode includes a slot through the second electrode from the first surface toward the second surface. The slot extends from a perimeter of the second electrode to an interior of the second electrode. The slot is configured to at least partially segment a surface area of the second electrode to reduce a radial current loop size in the second electrode. | 06-30-2011 |
20110160826 | IMPLANTABLE MEDICAL DEVICE INCLUDING EDDY CURRENT REDUCING CAPACITOR - An implantable device, such as a pacer, defibrillator, or other cardiac rhythm management device, can include one or more MRI Safe components. In an example, the implantable device includes a capacitor including a first electrode including a first slot extending from a perimeter of the first electrode to an interior of the first electrode. A second electrode is separated from the first electrode by a first distance. The second electrode includes a second slot extending from a perimeter of the second electrode to an interior of the second electrode. The first and second slots are configured to at least partially segment surface areas of the first and second electrodes, respectively, to reduce a radial current loop size in each of the first and second electrodes. | 06-30-2011 |
20110208280 | LEAD INCLUDING CONDUCTORS CONFIGURED FOR REDUCED MRI-INDUCED CURRENTS - Systems and methods for improving response of implantable leads to magnetic fields during medical procedures such as magnetic resonance imaging (MRI) are described. In various embodiments, the lead includes an inner conductor that is helically shaped and radially surrounded, at least in part, by one or more high-voltage conductors. The high-voltage conductor can be mechanically and/or electrically coupled, via a coupler, to the shocking coil. The pitch of the inner and/or outer conductor can be varied (e.g., continuously or at certain points) along the length of the lead. In some embodiments, the filar thickness, the pitch, and the mean coil diameter of the inner coil, the high voltage conductor coil, and the shock coil can be configured such that these coils have a desired inductance value when subjected to externally applied electromagnetic energy at radio frequencies commonly generated by MRI scanners (e.g., 40 MHz to 300 MHz). | 08-25-2011 |
20110276104 | METHOD AND APPARATUS FOR DISCONNECTING THE TIP ELECTRODE DURING MRI - 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. | 11-10-2011 |
20120071941 | SELECTIVELY CONNECTING THE TIP ELECTRODE DURING THERAPY FOR MRI SHIELDING - A medical device includes a pulse generator and an electrode configured to contact tissue in a body vessel. The medical device includes a lead that includes a lead connector. The lead connector connects a pulse generator with an electrode via a conductive path. An electrode switch is electrically connected between the lead conductor and the electrode. The electrode switch includes an open state preventing the conductive path between the lead and the electrode. The electrode switch includes a closed state establishing the conductive path between the lead and the electrode when a voltage is applied across the electrode switch that exceeds a threshold voltage. The electrode switch in the open state electrically shields the electrode from electromagnetic radiation and induced voltages during magnetic resonance imaging. | 03-22-2012 |
20120323297 | LEADS WITH HIGH RESISTIVE SURFACE - Implantable medical leads having resistance characteristics adapted to dissipate radio frequency (RF) electromagnetic energy during medical procedures such as magnetic resonance imaging (MRI) are disclosed. An illustrative medical device includes a lead having an inner electrical conductor operatively coupled to an electrode and a pulse generator, and one or more outer resistive shields that radially surround the inner conductor and dissipate RF energy into the surrounding body tissue along the length of the lead. | 12-20-2012 |
20130060314 | LEAD INCLUDING CONDUCTORS CONFIGURED FOR REDUCED MRI-INDUCED CURRENTS - An implantable medical device lead includes an inner conductor coil comprising one or more generally cylindrically wound filars. The inner conductor coil is configured to have a first inductance value greater than or equal to 0.2 μH/inch when the inner conductor coil is subjected to a range of radio frequencies. The implantable medical device lead also includes a multi-filar outer coil comprising two or more generally cylindrically wound filars. The multi-filar outer coil is configured to have a second inductance value greater than or equal to 0.1 μH/inch when the multi-filar outer coil is subjected to the range of radio frequencies. | 03-07-2013 |
20130123884 | MRI COMPATIBLE MEDICAL DEVICE LEAD INCLUDING TRANSMISSION LINE NOTCH FILTERS - A medical device lead includes a conductor and one or more band stop filters each coupled to the conductor and including a conductive coil. The one or more band stop filters are configured to attenuate an MRI-induced signal on the conductor. | 05-16-2013 |
20130310910 | LEAD INCLUDING CONDUCTORS CONFIGURED FOR REDUCED MRI-INDUCED CURRENTS - An implantable medical device lead includes an inner conductor coil comprising one or more generally cylindrically wound filars. The inner conductor coil is configured to have a first inductance value greater than or equal to 0.2 μH/inch when the inner conductor coil is subjected to a range of radio frequencies. The implantable medical device lead also includes a multi-filar outer coil comprising two or more generally cylindrically wound filars. The multi-filar outer coil is configured to have a second inductance value greater than or equal to 0.1 μH/inch when the multi-filar outer coil is subjected to the range of radio frequencies. | 11-21-2013 |
20140018896 | LEADS WITH HIGH SURFACE RESISTANCE - Implantable medical leads having resistance characteristics adapted to dissipate radio frequency (RF) electromagnetic energy during medical procedures such as magnetic resonance imaging (MRI) are disclosed. An illustrative medical device includes a lead having an inner electrical conductor operatively coupled to an electrode and a pulse generator, and one or more outer resistive shields that radially surround the inner conductor and dissipate RF energy into the surrounding body tissue along the length of the lead. | 01-16-2014 |
20140067030 | MRI COMPATIBLE LEAD COIL - Various embodiments concern leads having low peak MRI heating for improved MRI compatibility. Various leads include a lead body having at least one lumen, a proximal end configured to interface with an implantable medical device, and a distal end. Such leads can further include a conductor extending along at least a portion of the lead body within the at least one lumen and a defibrillation coil extending along an exterior portion of the lead body and in electrical connection with the conductor, wherein at least a section of the defibrillation coil is under longitudinal compression. The longitudinal compression can lower peak MRI heating along the defibrillation coil. The longitudinal compression may maintain circumferential contact between adjacent turns of the section of the defibrillation coil. | 03-06-2014 |
20140335422 | IMPLANTABLE MEDICAL DEVICE INCLUDING EDDY CURRENT REDUCING BATTERY - An implantable device, such as a pacer, defibrillator, or other cardiac rhythm management device, can include one or more MRI Safe components. In an example, the implantable device includes a battery including a first electrode and a second electrode separate from the first electrode. The second electrode includes a first surface and a second surface. The second electrode includes a slot through the second electrode from the first surface toward the second surface. The slot extends from a perimeter of the second electrode to an interior of the second electrode. The slot is configured to at least partially segment a surface area of the second electrode to reduce a radial current loop size in the second electrode. | 11-13-2014 |
20140364714 | ANTENNAS FOR IMPLANTABLE MEDICAL DEVICES - In general, techniques are described for wirelessly transferring information using an implantable antenna. In one example, an apparatus includes an implantable medical device that includes a housing including an implantable telemetry circuit. The apparatus includes a dielectric compartment, mechanically coupled to the housing and including first and second substantially parallel face portions, and a third face portion extending between the first and second face portions, and an antenna assembly configured to be mechanically attached to the dielectric compartment and configured to be electrically coupled to the implantable telemetry circuit, the antenna assembly includes a spiral conductor comprising first, second, and third spiral conductor portions that extend adjacent the first, second, and third face portions, respectively, of the dielectric compartment, where the first, second, and third spiral conductor portions define an interior region, and where at least a portion of the third spiral conductor portion extends inwardly into the interior region. | 12-11-2014 |