A system for communicating with a medical device implanted in an ambulatory patient and for locating the patient in order to selectively monitor device function, alter device operating parameters and modes and provide emergency assistance to and communications with a patient. The implanted device includes...http://www.google.com/patents/US6083248?utm_source=gb-gplus-sharePatent US6083248 - World wide patient location and data telemetry system for implantable medical devices
