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.

Implantable medical systems enter an exposure mode of operation, either manually via a down linked programming instruction or by automatic detection by the implantable system of exposure to a magnetic disturbance. A controller then determines the appropriate exposure mode by considering various pieces of information including the device type including whether the device has defibrillation capability, pre-exposure mode of therapy including which chambers have been paced, and pre-exposure cardiac activity that is either intrinsic or paced rates. Additional considerations may include determining whether a sensed rate during the exposure mode is physiologic or artificially produced by the magnetic disturbance. When the sensed rate is physiologic, then the controller uses the sensed rate to trigger pacing and otherwise uses asynchronous pacing at a fixed rate.

The present invention provides an active implantable medical device (AIMD) comprising an implantable lead, an application specific integrated circuit (ASIC) within a hermetic enclosure of the AIMD, and a sensing and cancellation wave output from the ASIC supplying to the lead. The invention also provides a method of reducing heating of an AIMD and a lead thereof.

An implantable pulse generator including a header, a can, and a filtered feedthrough assembly. The header including lead connector blocks. The can coupled to the header and including a wall and an electronic substrate housed within the wall. The filtered feedthrough assembly including a flange mounted to the can and having a feedthrough port, a plurality of feedthrough wires extending through the feedthrough port, and an insulator brazed to the feedthrough port of the flange. The filtered feedthrough assembly further including a capacitor having the plurality of feedthrough wires extending there through, an insulating washer positioned between and abutting the insulator and the capacitor at least in the area of the braze joint such that the capacitor and the braze joint are non-conductive, and an electrically conductive material adhered to the capacitor and the flange for grounding of the capacitor.

An enhanced RF switchable filtered feedthrough for real-time identification of the electrical and physical integrity of an implanted AIMD lead includes a DOUBLE POLE RF switch disposed on the device side. Additionally, the RF switchable filtered feedthrough can optionally include transient voltage suppressors (TVS) and an MRI mode. In an embodiment, a DOUBLE POLE RF switch selectively disconnects EMI filter capacitors so that an RF test/interrogation signal is sent from the AIMD down into an implanted lead(s). The reflected RF signal is then analyzed to assess implanted lead integrity including lead body anomalies, lead insulation defects, and/or lead conductor defects. The Double Pole switch is configured to be controlled by an AIMD control signal to switch between FIRST and SECOND THROW positions. In the FIRST THROW position a conductive leadwire hermetically sealed to and disposed through an insulator is electrically connected to a filter capacitor, which is then electrically connected to the ferrule of a hermetic feedthrough of an AIMD. In the FIRST THROW position, EMI energy imparted to a body fluid side implanted lead can be diverted to the housing of the AIMD. In the SECOND THROW position the conductive leadwire is electrically connected to an RF source disposed on the device side of the housing of the AIMD. While in the SECOND THROW position, a reflective return signal from the RF source is measured and analyzed to determine if the implanted AIMD lead exhibits any life-threatening performance issues, such as lead body anomalies, lead insulation defects or changes, or even defective, fractured or dislodged lead conductors. In another embodiment, a SINGLE POLE RF switch is configured to disconnect filter capacitors during the delivery of a high-voltage cardioversion shock from an implantable cardioverter defibrillator. Dis-connection of the filter capacitor either reduces or eliminates filter capacitor pulse inrush currents, which allows for the use of standard low-voltage filter capacitors instead of larger and more expensive high-voltage pulse rated filter capacitors. Dis-connection of the filter capacitor also allows for an RF interrogation pulse to be applied to the implanted lead in real-time (for example, pre-set intervals throughout the day).

An implantable medical device, including a magnet apparatus and a support body supporting the magnet apparatus, wherein the magnet apparatus has a long axis and a short axis shorter than the long axis normal to the long axis and at least one of the top surface or the bottom surface of the magnet apparatus establishes a curved outer periphery with respect to a cross-section lying on a plane on which the long axis lies and which is parallel to the short axis.

Medical devices provide metallic connector enclosures. The metallic connector enclosures may be constructed with relatively thin walls in comparison to polymer connector enclosures to aid in miniaturizing the medical device. The metallic connector enclosures may be constructed with interior surfaces that deviate less from an ideal inner surface shape in comparison to polymer connector enclosures to allow for better concentricity of electrical connectors. The metallic connector enclosures may include a panel that allows access to the cavity of the connector enclosure where set screw blocks, lead connectors, spacers, seals, and the like may be located. Furthermore, the lead connectors within the metallic connector enclosures may be separated from the metallic connector enclosure by being positioned within non-conductive seals that reside within features included in cavity walls of the connector enclosure. Similarly, set screw blocks may be separated from the metallic connector enclosure by non-conductive spacers present within the cavity.

Medical lead bodies that are paired each include a braided conductive shield. The braided conductive shield of one lead body has a value for a physical parameter that differs from a value for the physical parameter of the second lead body. The difference in values of the physical parameter for the paired lead bodies results in a reduction in heating from exposure of the lead bodies to radiofrequency energy at electrodes associated with the lead bodies. The lead bodies may be paired by being implanted adjacently to one another. The lead bodies may be further paired by being coupled to a same distal body, such as a paddle containing the electrodes.

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.