FASS-ECG: A FHIR Cloud API to Enable Streaming and Storage of Continuous 12-leads ECGs

The interoperability between health web applications (eHealth) is one of the main challenges to fully adopting the broad range of applications like IoT devices, wearable devices, APIs, web apps, and mobile apps, among others. FHIR (Fast Healthcare Interoperability Resources) stands out concerning interoperability because the design focus on eHealth to offer a flexible, scalable, and lightweight approach to healthcare data exchange. In particular, electrocardiograms (ECGs) include transmission, management, and storage challenges due to their stream-like characteristic of the information. Researchers have proposed ECG streaming by ignoring or modifying the FHIR standards. This work proposes FASS-ECG, a FHIR-compatible cloud API for streaming ECGs. FASS-ECG contains endpoints for reading and writing long-term ECGs distributed in multiple web requests. Two FASS-ECG designs are investigated to process, store, and persist one ECG record despite the distributed transmission. FASS-ECG designs rely on object storage software and data partitioning in the database. The results show that both FASS-ECG designs can stream ECGs fully compatible with FHIR standard records. In particular, long-term ECG writing can increase response times more than 4 x without the storage techniques employed in FASS-ECG. We validate the FHIR interoperability of FASS-ECG against an open source complete implementation of the FHIR.