As mobile devices are enhanced continuously with more resources, wireless infrastructures provide support to a growing number of assistive environments. Among the potential domains which can suffice from their deployment, is the e-healthcare sector. The increased sensitivity requirements imposed by the US and EU legislation, urge towards the design and incorporation of strict security standards in the deployment process of wireless e-healthcare infrastructures. Even though mobile devices are characterized by an increase in processing and autonomy capacity, the necessity to encrypt all communications consists of a significant burden. In this paper we present W-EHR, a wireless architecture that enables authorized medical personnel to access medical records in a secure and transparent manner, utilizing an agent based architecture. Ubiquitous access to medical information within the hospital range is achieved using mobile devices; security management is achieved using a hierarchical policy based approach in compatibility with the IETF policy-based management model. In order to comply with the strict privacy requirements, all the transactions are encrypted using a hybrid approach that employs symmetric and asymmetric encryption techniques. We describe our experiments that prove the effective operation of our infrastructure (by means of device resources consumption and network bandwidth). In our calculations we consider the encryption overhead when transmitting medical records in a compatible with medical codification standards form.