Patent ID: 8433412

Claim:
A respiration sensing and stimulation system for use with an implantable medical device comprising: a. an intravascular azygos lead with at least one electrode configured to be located in an azygos vein; b. an implantable medical device with at least one electrode configured to be implanted subcutaneously in a patient's chest; c. circuitry within the implantable medical device configured to measure impedance between the at least one electrode on the azygos lead when the electrode is located in an azygos vein of a patient and the at least one electrode on the implantable medical device when the device implanted subcutaneously in the patient; and d. at least one stimulation electrode that is configured to be positioned proximate a phrenic nerve; and e. circuitry within the implantable medical device configured to stimulate the phrenic nerve using the stimulation electrode.