The advent of Wireless Body-Area Sensor Networks (WBASNs) technologies enables the autonomic and remote collection of real- time physiological data related to the health status of patients with chronic diseases. At the same time the advances in wireless communication systems make possible the “anywhere, anytime” delivery of such data to medical staff and caregivers in order to allow them to easily monitor and quickly respond in emergencies. In this paper, we propose a system architecture that utilizes the IMS (IP Multimedia Subsystem) and the HL7 (Health Level Seven) technologies to implement a mobile and interoperable healthcare system to support WBASNs in a healthcare environment.