Medtronic, Inc.

Mark W Sandberg

John J Grevious

Thomas J Winkler

Kenneth L Graves

Ray W Gravlin

Anne J Van Leeuwen

A method and apparatus for programming implantable medical devices employing RF telemetry, and more particularly, altering the RF telemetry antenna Q to accommodate telemetry with implantable medical devices having differing RF telemetry receiving characteristics is disclosed. The RF head telemetry antenna comprises an LC tank circuit including an RF head telemetry coil and a tuning capacitor and has a predetermined antenna Q. The RF head telemetry antenna is adapted to be driven into oscillation by applied oscillating energy and to continue to oscillate in a series of declining amplitude oscillations after the oscillating energy is no longer applied as residually stored oscillating energy is dissipated therethrough. A transmit telemetry pulse is generated for establishing a pulse width of the telemetry RF pulse. Upon the termination of the telemetry transmit pulse antenna Q is reduced from the predetermined antenna Q, and the declining amplitude oscillations are thereby attenuated. The reduction of the antenna Q is effected by a grounding a sense coil located in the programmer RF head that is employed to sense the RF pulse and regulate the amplitude thereof during the transmit telemetry pulse at the termination of the transmit telemetry pulse.

Method and apparatus for altering the Q of an implantable medical device

A method and apparatus for providing electrical field (E-field) shielding for electro-magnetic devices. In one embodiment of the invention, a programming head from an implantable medical device programming system is housed within a nonconductive exoskeleton. The programming head contains an antenna that is preferably shielded from E-fields but not from magnetic fields (H-fields). A pattern of electrically conductive material, such as a nickel-acrylic paint or the like, is applied to interior surfaces of the exoskeleton, such that at least two (preferably four) distinct and discontinuous areas of conductive material are defined thereon. A collar for providing strain relief for a programming head cable entering through an aperture in the exoskeleton is maintained in electrical contact with each area of conductive material in said exoskeleton. The collar is preferably made of conductive material, and is also coupled to at least one conductor in the programming head cable, such that the conductive areas are coupled to ground via the cable. In other embodiments, both E-shielding and H-shielding may be similarly accomplished by coating the entire inner surface of the exoskeleton.

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Coon Rapids, MN, United States of America

Mark W Sandberg