This PHP Sample Source Code is athenahealth's More Disruption Please API samples. The libraries are used to help facilitate access to the API. Each package has a naive implementation of using the API, as well as a library and a testing script to use that library.
Zynx Health has announced a RESTful API that's compliant with the Fast Healthcare Interoperability Resources (FHIR) standard data format. As providers of other EHR systems offer similarly compliant systems, patient data will theoretically flow with less friction across medical practitioners.