Abstract: An implantable medical device includes a housing comprising a titanium alloy selected from the group consisting of Ti-4.5Al-3V-2Fe-2Mo-0.15O, Ti-4Al-2.5V-1.5Fe-0.25O, Ti-6Al-2Sn-4Zr-2Mo, Ti-3Al-2.

Abstract: An implantable medical device includes a control circuit for controlling the operation of the device and for obtaining physiological data from a patient in which the medical device is implanted. The implanted device also includes a communication circuit for transmitting the physiological data to an external device. A first power source is coupled to the control circuit and provides power to the control circuit. A second power source is coupled to the communication circuit and provides power to the communication circuit.

Abstract: An apparatus and method that will allow for external communication, via an external programmer, for positive device identification and for retrieval of device or patient information stored by an implantable medical device with a depleted power source. The external programmer will deliver energy to a secondary power source located inside the implanted device using RF telemetry sufficient to charge up the secondary power source, e.g., a small capacitor. The capacitor will charge up immediately within milliseconds. Once the secondary power source is sufficiently charged, it can be used to power up a controller having the stored information in the implantable medical device. Once the controller is operational, the implanted device will transmit device and patient information to the external programmer via RF telemetry.

Abstract: An apparatus and method for a telemetry system that automatically selects a symmetric modulation protocol configuration for telemetry communication between medical devices and programmers used in providing patient treatment. The standardized telemetry protocol will use the symmetric modulation protocol configuration to establish a downlink or uplink connection. The standardized telemetry protocol will automatically select the appropriate modulation protocol configuration depending on the modulation format and data rate capability best suited for the components needing to communicate via telemetry.

Abstract: Downlink telemetry for an implantable medical device includes controlling downlink energy by generating a downlink strength signal representative of the strength of one or more downlink control bursts transmitted from an external communication device and received at the receiver of the implantable medical device. The peak amplitude of modulated downlink data bursts is controlled by adjusting the burst duration of the ramped envelope of such downlink data bursts as a function of the downlink strength signal.

Abstract: 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.

Abstract: A method and apparatus for transmitting information-encoded, telemetry signals percutaneously between an implanted medical device and an external device as telemetry RF pulses which are modulated in pulse position and/or in pulse width within a telemetry frame comprising at least a telemetry frame boundary RF pulse and a telemetry frame data RF pulse. Data to be transmitted in a given telemetry frame is encoded into a PPM code for positioning at least certain telemetry RF pulses at pulse positions of the telemetry frame and a PWM code for establishing the pulse widths of at least certain telemetry RF pulses of the telemetry frame. The telemetry frame is formatted from the PPM code, and the telemetry RF pulses are generated at the formatted pulse positions within the telemetry frame. The pulse widths of the telemetry RF pulses are controlled in accordance with the PWM code for the certain telemetry RF pulses.

Abstract: An efficient low cost means for regulating the output level of a magnetic field transmitter. A feedback coil tightly coupled to an output coil is designed to produce an output voltage just above the supply level for the output stage of the transmitter when the desired output level is achieved. The feedback sense coil tightly coupled to an output coil is designed to produce an output voltage just above a regulated power supply level for the output stage of the transmitting antenna until a desired output level is achieved. The feedback coil is diode coupled to the regulated power supply lines of the transmitter. When the output level increases above the regulation level the diodes begin to conduct returning energy to the supply and preventing further increase of the transmitting antenna signal.

Abstract: 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.

Abstract: A closed loop system for attaining premium telemetry performance for vector field electromagnetically coupled telemetry systems. The disclosed system utilizes a linear ramped envelope for downlink RF bursts, resulting in a detected pulse width in the implanted device which is proportional to the downlink detection margin. The detected pulse width, when uplink telemetered to an external programming unit allows the programming unit to generate a telemetry status feedback signal for the user positioning the programming head with respect to the implant site. Feedback based upon both uplink and downlink signal strength in especially advantageous in dual-coil systems where there are distinct and unique coupling coefficients for uplink and downlink.

Abstract: A method of and apparatus for telemetering both analog and digital data transcutaneously between an implantable medical device and an external receiver, such as between an external programmer and an implantable cardiac pacer. A damped carrier at 175 kilohertz is pulse position modulated by digital data. The data, along with synchronization and identification codes, are positioned into predefined ranges within predefined frames as measured by individual time periods. The data is uniquely identified by the position of a burst of the carrier within the predefined range. An automatically initiated hand shake protocol maintains the link over slight variations in programmer head position with an indicator notifying the operator when repositioning is required. Analog data may be transferred in digital form or alternatively transferred using phase modulation of the carrier bursts. A cyclic redundancy code is used for link error detection.