Patent ID: 8321003

Claim:
A system for characterizing myocardial ischemia, comprising: an implantable static exertion sensor configured to output an exertion signal responsive to patient static exertion, the exertion signal containing static exertion data; at least one implantable physiological parameter sensor configured to output a physiological signal responsive to a physiological parameter, the physiological signal containing physiological exertion-response data, the at least one implantable physiological parameter sensor comprising: an implantable extra-cardiac parameter sensor configured to output an extra-cardiac signal responsive to an extra-cardiac parameter, the extra-cardiac signal containing extra-cardiac response data; and an implantable cardiac parameter sensor configured to output a cardiac signal responsive to a cardiac parameter, the cardiac signal containing cardiac response data; memory; and a processor configured to execute program instructions stored in memory to cause the system to: identify steady state periods of physiological exertion based on the static exertion data and assign one of a plurality of exertion intensity levels to each of the steady state periods; organize the physiological exertion-response data according to the assigned exertion intensity levels of the identified steady state periods of physiological exertion during which the physiological exertion-response data was respectively output; compare the physiological exertion-response data with stored physiological response information associated with equivalent levels of physiological exertion intensity of the steady state periods to which the physiological exertion-response data is organized; and determine the likelihood that myocardial ischemia occurred during one or more of the periods based on the comparison of the physiological response information to the physiological exertion-response data, wherein: processor organization of the physiological response data comprises organizing the respective extra-cardiac response and cardiac response data according to the assigned exertion intensity levels of the identified steady state periods of physiological exertion during which the extra-cardiac response and cardiac response data was respectively output; processor comparison of the physiological exertion-response data with stored physiological response information comprises respectively comparing the extra-cardiac and cardiac response data with extra-cardiac and cardiac response information associated with equivalent levels of physiological exertion intensity of the steady state periods to which the extra-cardiac and cardiac response data is organized; and determining the likelihood that myocardial ischemia occurred during one or more of the periods is based on the comparison of the extra-cardiac and cardiac response data to the extra-cardiac and cardiac response information.