Implantable medical device employing single drive, dual sense impedance measuring

Abstract

A method and system is implemented in an implantable medical device (IMD) and provides for the detection of multiple physiologic parameters in response to a single source current event. A high frequency source current signal is propagated through body tissues in the thorax, including the heart. The source current signal has a frequency greater than a frequency of a pacing current signal producible by the IMD. In response to the source current signal, a first voltage is detected between two portions of a first region of the heart substantially concurrently with sensing a second voltage between one of the IMD housing and a header/can electrode and one of the two portions of the first region of the heart. The first voltage is associated with a cardiac function and the second voltage is indicative of a respiratory function. The source current signal may be a single or multiple cycle current pulse. The source current signal may also be a continuous current signal. The source current signal may take the form of a monophasic current pulse or have a polyphasic character, such as in the case of a biphasic current pulse.

Dependencies are inferred from the claim text.