An implantable medical device includes operational circuitry, such as a therapy circuit. The implantable medical device also includes a power source configured to deliver energy to the operational circuitry, and a deactivation element configured to disable the therapy circuit. A power manager is configured to detect an end-of-life condition of the power source and, in response to detecting the end-of-life condition, cause the deactivation element to reversibly disable the therapy circuit.