Cardiac Pacemakers, Inc.

Micron Technology Incorporated

Steven D Check

Jesse W Hartley

Nicholas J Stessman

James P Nelson

Scott A Reedstrom

Marc H Cohen

Nathan A Eckel

An apparatus comprises an encryption key generator to generate a media encryption key to encrypt data in number of memory components, where the encryption key generator is configured to wrap the media encryption key to generate an encrypted media encryption key, The encrypted media encryption key is stored in a non-volatile memory. The apparatus comprises firmware having instructions to transition the apparatus to and from a secure state using the encrypted media encryption key.

Key encryption handling

A cardiac rhythm management (CRM) device detects transthoracic impedance, extracts ventilation or other information, and adjusts a delivery rate of the CRM therapy accordingly. A four-phase sequence of alternating direction current pulse stimuli is periodically delivered to a patient's thorax. A transthoracic impedance signal is extracted using a weighted demodulation. Signal processing extracts ventilation information and removes cardiac stroke information using an adaptive lowpass filter. The adaptive filter cutoff frequency is based on the patient's heart rate; a higher cutoff frequency is provided for higher heart rates. Peak/valley detection indicates tidal volume, which is integrated to extract minute ventilation (MV). Short and long term averages are formed and compared to establish a MV indicated rate. Rate adjustment ignores MV information when a noise-measurement exceeds a threshold. An interference avoidance circuit delays delivery of the stimuli when telemetry pulses or other interfering signals are detected.

Rate adaptive cardiac rhythm management device using transthoracic impedance

Rate adaptive cardiac rhythm management device using transthoracic

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Eden Prairie, MN, United States of America

Steven D Check