Proof of concept for an international long-time preservation ECG format

We present a proof-of-concept of a medical data format for storing and retrieving 12-lead, 10-second standard electrocardiograms (ECG). The new format combines a digital ECG record into a standard graphical report (PDF). Using the very recent PDFIA-3 standard (ISO 190053:2012), we designed a long-term preservation graphic report (such as a standard 3 χ4 or 6χ2 ECG printout) in which the original ECG digital data (using the aECG ANSIIHL7 R1-2004 format) is embedded as a compressed attachment. The proposal also includes two ways of ensuring conformity between the ECG vector images and the digital data. First, a digital signature is added to guarantee that the document was not modified after creation. Second, specific metadata are inserted to allow a direct digital comparison between the vector ECG printout and the data. To prove the feasibility of the approach, 93 aECGs, selected from diferent device manufacturers, resolutions and sample rates, were converted into the new format and then validated. Diferences between digital data and vector graphics were always smaller than 0.02 f.1 V, significantly below the typical AID converter resolution.