Cardiac Pacemakers, Inc.

Richard E Stindt

Mark D Amundson

Thomas C Wright

An improved bio-medical telemetry apparatus for programming an implanted medical device includes a large substantially planar and concentrically wound first telemetry coil. The coil is disposed inside a thin flexible housing including layers of insulative materials to prevent electrical contact between loops of the first telemetry coil and to hold the first telemetry coil formed shape in place. The apparatus further includes a communication lead coupled to the first telemetry coil for communicating with a medical device programmer. During a telemetry session the first telemetry coil including the flexible housing is disposed at a posterior location of the torso and an implanted medical device disposed subcutaneously on an anterior location of the torso. During programming the first telemetry coil is inductively coupled to the implanted medical device for wireless data communication with the implanted medical device. The large, substantially planar design of the first telemetry coil permits more even and large flux paths, which allow for less precise positioning of the apparatus with respect to the implanted medical device. Also, the flexible housing conforms to irregular surface of patient's and supporting furnishing providing comfort to patients lying upon the first telemetry coil during telemetry sessions.

Inductive coil apparatus for bio-medical telemetry

An electronic switching circuit for use in a demand-type cardiac pacer for (1) allowing the amplitude of the stimulating pulses to be selected, (2) ensuring a high input impedance for the heartbeat sensing amplifier, and (3) ensuring a low recovery time following the generation of a pacer pulse. Disposed between the heart contacting electrodes and the sensing amplifier is an electronic switch which is closed during a predetermined period (the sensing interval), but which is opened when the pulse generator is producing a pacer pulse. Thus, the sensing amplifier is shielded from receiving the high voltage surge occasioned by the application of a pacer pulse to the heart. Similarly, an electronic switching device is interposed between the pulse generator and the heart contacting electrodes, which device is closed during a pacing interval, but open during the aforesaid sensing interval, thus isolating the sensing amplifier from the pacer circuitry. Included in the system is a voltage doubler and associated switches which can selectively double or not double the amplitude of the stimulating pacer pulse. In either event, the charge on the voltage doubling capacitor is recovered through the heart in a relatively short time following the cessation of a pacer pulse.

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Coon Rapids, MN, United States of America

Richard E Stindt