The present invention generally relates to heart treatment systems. In some aspects, methods and systems are provided for facilitating communication between implanted devices. For example, an implantable cardiac rhythm management device may be configured to communicate with an implantable blood pump. The implantable cardiac rhythm management device may deliver heart stimulation rate information in addition to information associated with any detected abnormalities in heart function. In response, the pump may be configured to adjust pumping by the pump to better accommodate a patient's particular needs.