Cardiac Pacemakers, Inc.

Thomas M Bocek

Mark Rutzer

Karl F Gauglitz

Blair Erbstoeszer

Lorin W Matthews

William E Reagor

William J Linder

Joseph M Bocek

Michael J Lyden

Nicholas J Stessman

Kenneth Frederick Cowan

Scott R Vanderlinde

Prashant Brijmohansing Rawat

Mehdi Katoozi

Systems and methods for sensing external magnetic fields in implantable medical devices are provided. One aspect of this disclosure relates to an apparatus for sensing magnetic fields. An apparatus embodiment includes a sensing circuit with at least one inductor having a magnetic core that saturates in the presence of a magnetic field having a prescribed flux density. The apparatus embodiment also includes an impedance measuring circuit connected to the sensing circuit. The impedance measuring circuit is adapted to measure impedance of the sensing circuit and to provide a signal when the impedance changes by a prescribed amount. According to an embodiment, the sensing circuit includes a resistor-inductor-capacitor (RLC) circuit. The impedance measuring circuit includes a transthoracic impedance measurement module (TIMM), according to an embodiment. Other aspects and embodiments are provided herein.

Systems and methods for sensing external magnetic fields in implantable medical devices

An ambulatory or implantable device, such as a pacer, defibrillator, or other cardiac rhythm management device, can tolerate magnetic resonance imaging (MRI) or other noise without turning on an integrated circuit diode by selectively providing a bias voltage that can overcome an expected induced voltage resulting from the MRI or other noise.

Implantable device with bias for MRI

An apparatus comprises a transceiver configured to communicate wirelessly with an IMD and a processor communicatively coupled to the transceiver. The processor is configured to detect an error in a data unit received from the IMD, transmit a series of synchronization signals during an uninterrupted communication sequence, and receive, for each synchronization signal, a new data unit and the number of requested duplicate data units from the IMD. Each synchronization signal includes an echo code, wherein the echo code corresponds to a request for a number of duplicate data units to be sent in response to detecting the error in the data unit received during said uninterrupted communication sequence. The number of duplicate data units corresponds to a value of the echo code, and a duplicate data unit corresponds to a data unit previously transmitted by the IMD during said uninterrupted communication sequence.

On-demand retransmission of data with an implantable medical device

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Seattle, WA, United States of America

Thomas M Bocek