Data Points for any object may be stored in many physical stores. Any access point provides connectivity to all EKG content regardless of where it resides.
The physical stores could include traditional databases as well as varied EKG/Platforms specifically designed for hosting EKGs. And some which may be hosted outside the enterprise including by information services or governments. All seamlessly accessed using W3C (internet-based) protocols which also allow for browser or API linked data traversal and query.
Federating different systems allows the knowledge available to an enterprise to be accessed as a whole. It allows best of breed systems to be used for specific purposes, and evolved over time without disrupting the EKG as a whole. It allows scalability through adding new hardware, swapping out systems, and optimizing access through moving data closer to where it needs to be processed.
The potential for a loose and evolving nature does mean some degree of monitoring of access patterns and performance; and service level agreements for vital information access.