Patent ID: 8914101
Filing Date: 2014-12-16
Classification: A61B

Abstract:
1. A method of detecting a thoracic fluid condition in an implantable medical device system, comprising: periodically measuring intrathoracic impedance for one of a plurality of intrathoracic measurement vectors using a pair of a plurality of electrodes implanted along the thoracic cavity of a patient, the one of the plurality of intrathoracic measurement vectors selected as representative of a global intrathoracic impedance of the patient, wherein the global intrathoracic impedance is sensitive to an intrathoracic impedance change with low specificity as to a location of the intrathoracic impedance change; detecting, based on the periodic measurements, the intrathoracic impedance change for the one of the plurality of intrathoracic measurement vectors representative of the global intrathoracic impedance of the patient, wherein the intrathoracic impedance change is a trigger for intrathoracic impedance measurements for the plurality of intrathoracic measurement vectors; in response to detecting the intrathoracic impedance change, measuring intrathoracic impedance for the plurality of intrathoracic measurement vectors using the plurality of electrodes; in response to measuring the intrathoracic impedances, computing a conductivity of each of a plurality of intrathoracic impedance mapping locations corresponding to the plurality of intrathoracic measurement vectors, wherein each of a plurality of anatomic regions is associated with a respective one or more of the mapping locations; detecting a change in conductivity for one or more of the mapping locations based on the computed conductivities of the mapping locations; detecting the thoracic fluid condition in response to the detected change in conductivity; and discriminating, by a processor, within which one or more of the plurality of anatomic regions the thoracic fluid condition occurred based upon for which of the mapping locations the change in conductivity was detected.