Patent ID: 8131367

Claim:
An implantable medical device for delivering a therapeutic output to a patient, comprising: an electrical power source having a useful life and a voltage which declines over said useful life; a therapeutic delivery device operatively coupled to said power source and adapted to deliver said therapeutic output to said patient; and a power source longevity monitor operatively coupled to said power source and said therapeutic delivery device, comprising: an energy counter for counting the amount of energy used by said implantable medical device; an energy converter for converting said energy used into an estimate of remaining power source longevity and generating an energy longevity estimate; a voltage monitor for monitoring said voltage of said power source; a voltage converter for converting said voltage monitored by said voltage monitor into an estimate of remaining longevity of said power source and generating a voltage longevity estimate; and a calculator operatively coupled to said energy converter and to said voltage converter, said calculator predicting said power source longevity using a combination of both of said energy longevity estimate and said voltage longevity estimate.