A system for validating safety of a medical device in a presence of a magnetic resonance imaging (MRI) field is provided. The system includes a first electric field generating device configured to form first electric field and configured to receive a medical device at least partially within the first electric field, and a second electric field generating device configured to form a second electric field in proximity to the first electric field and configured to receive the medical device at least partially within the second electric field. One or more processors are configured to execute program instructions to calculate predicted parameter values of the medical device based on a transfer function, the transfer function defined to predict a safety characteristic of the medical device when in the presence of an MRI field, obtain measured parameter values from the medical device, the measured parameter values indicative of the safety characteristic of the medical device when exposed to the first and second electric fields, and compare the measured parameter values to the predicted parameter values in connection with validating the transfer function.

A hermetically sealed feedthrough assembly for an active implantable medical device having an oxide-resistant electrical attachment for connection to an ENI filter, an EMI filter circuit board, an AIMD circuit board, or AIMD electronics. The oxide-resistant electrical attachment, including an oxide-resistant coating layer that is disposed on the device side surface of the hermetic seal ferrule over which an optional ECA stripe may be provided. The optional ECA stripe may comprise one of a thermal-setting electrically conductive adhesive, an electrically conductive polymer, an electrically conductive epoxy, an electrically conductive silicone, an electrically conductive polyamide, or an electrically conductive polyimide, such as those manufactured by Ablestick Corporation. The oxide-free coating layer may comprise one of gold, platinum, palladium, silver, iridium, rhenium, rhodium, tantalum, tungsten, niobium, zirconium, vanadium, and combinations or alloys thereof. As used herein, the oxide-free coating layer is not limiting and as will be taught, in addition to sputtering, there are many other methods of applying a proud oxide-free surface on either an AIMD ferrule or am AIMD housing.

A shield located within an implantable medical lead may be terminated in various ways at a metal connector. The shield may be terminated by various joints including butt, scarf, lap, or other joints between insulation layers surrounding the lead and an insulation extension. The shield may terminate with a physical and electrical connection to a single metal connector. The shield may terminate with a physical and electrical connection by passing between an overlapping pair of inner and outer metal connectors. The metal connectors may include features such as teeth or threads that penetrate the insulation layers of the lead. The shield may terminate with a physical and electrical connection by exiting a jacket of a lead adjacent to a metal connector and lapping onto the metal connector.

An implantable medical device includes an enclosure sleeve and a top cap. The enclosure sleeve comprises an enclosure wall with at least a portion of the enclosure wall comprising the grade 5 titanium and having a thickness between 0.007 inches and 0.009 inches. The enclosure sleeve includes an open top end and an open bottom end that is opposite the open top end. The top cap includes a feedthrough block, a first top cap end portion, and a second top cap end portion. The first top cap end portion is configured to couple to the open top end of the enclosure sleeve, and the second top cap end portion configured to be positioned within the enclosure sleeve.

One or more antennas are electrically coupled to one or more switches of an implantable medical device (IMD) in which the one or more switches are additionally electrically coupled to one or more lead wires of an IMD lead. The one or more switches also are electrically coupled to one or more electrodes or electrical circuitry of the IMD's implantable pulse generator (IPG). In response to exposure of the IMD to an energetic electromagnetic field, a voltage signal is induced in the one or more antennas and provided, possibly via one more filters, as a control signal to the one or more switches. Receipt of the control signal by the one or more switches automatically configures the one or more switches into a non-conductive state, thereby electrically isolating the one or more lead wires from the one or more electrodes or the IPG electrical circuitry.

An electrode system includes an electrode, a connector, and a cable with an in-line radio-frequency filter module comprising resistors and inductors without any deliberately added capacitance. The resistors are arranged in an alternating series of resistors and inductors, preferably with resistors at both outer ends, and connected electrically in series. The in-line module is located at a specific location along the wire, chosen through computer modeling and real-world testing for minimum transfer of received RF energy to a patient's skin, such as between 100 cm and 150 cm from the electrode end of a 240 centimeter cable. The total resistance of the resistors plus cable, connectors and solder is 1000 ohms or less; while the total inductance is roughly 1560 nanohenries. The inductors do not include ferrite or other magnetic material and are, together with the resistors, stock components thereby simplifying manufacture and reducing cost.

In one embodiment, an implantable pulse generator (IPG) for providing a neurostimulation therapy, comprises: pulse generation circuitry and pulse delivery circuitry for controlling generation and delivery of electrical pulses to a patient using one or more electrodes of a stimulation lead; measurement circuitry for determining characteristics of one or more electrodes selected for delivery of electrical pulses; and a processor for controlling the IPG according to executable code; wherein the IPG is adapted to calculate values for an impedance model of the one or more selected electrodes using the determined plurality of voltage measurements and to adjust current levels for the exponentially decreasing current pattern based on the calculated values for the impedance mode.

A cochlear implant including a cochlear lead, an antenna, a stimulation processor, and a magnet apparatus, associated with the antenna, including a case and a magnet assembly, having a spine and at least one magnet that is secured to the spine, that is located within the case and is rotatable relative to the case.

A medical sensing system (100) includes an elongate interventional device (101) and an adjustable capacitance circuit (102). The elongate interventional device (101) includes a sensor (103) having a capacitance (C.sub.ss). The elongate interventional device (101) also includes a first electrical conductor (104) and a second electrical conductor (105). The first electrical conductor (104) and the second electrical conductor (105) are in electrical contact with the sensor (103) and extend along the elongate interventional device (101). The elongate interventional device (101) also includes i) an electrically conductive shield (106) that overlaps the electrical conductors (104, 105) and/or ii) an electrically conductive shaft (107). The adjustable capacitance circuit (102) provides an adjustable capacitance (C.sub.Adj1, C.sub.Adj2) between at least one of the electrical conductors (104, 105) and i) the electrically conductive shield (106) that overlaps the electrical conductors (104, 105) and/or ii) the electrically conductive shaft (107).

Connector enclosure assemblies for medical devices provide an angled lead passageway. The lead passageway which is defined by electrical connectors and intervening seals within the connector enclosure assembly establishes the angle relative to a base plane of the connector enclosure assembly. Various other aspects may be included in conjunction with the angled lead passageway, including an angled housing of the connector enclosure assembly, feedthrough pins that extend to the electrical connectors where the feedthrough pins may include angled sections, and a set screw passageway set at an angle relative to the lead passageway to provide fixation of a lead within the lead passageway.