A method carried out by an implantable medical device (IMD) for coordinating performance of one or more designated functions includes waiting in a low-power state for a predetermined event, detecting the predetermined event, and, responsive to detecting the predetermined event, searching for a wake-up command from a coordinating device implanted in the human body. The method further includes, receiving the wake-up command, and responsive to receiving the wake-up command, performing the one or more designated functions, and returning to the low-power state. A system includes a network of one or more implantable medical devices (IMDs) implanted in a human body. The system includes a satellite IMD operable to change between a plurality of power states, search for a wake-up command, and transmit an identification signal. The system may include a primary unit operable to receive the signal and coordinate a wake-up time based on the signal.