Hi Seng,
For lead measurements - at least the basic ones like “Global” and lead specific - there are LOINC based concepts in the standard OMOP vocabularies. Some measurements programs like those from Physio-Control have the basics, while those from Philips TC50/70 for example have more extensive global and lead measurements available - so you will need to have both a custom and “standard” mappings - at least that is how I’m handling this for GE12SL, Philips, and GLASGOW based electrocardiographs and defibrillators.
Then there is the concept mapping of the 12-lead Interpretation statements, modifiers, and qualifiers - again dominated by GE12SL, Philips 0B, and GLASGOW. On top of that - I assume you would be mostly interested in confirmed 12-lead ECGs (vs unconfirmed) - which means you will have place holders for over-read cardiologist free text entries, edits, and deletions if you really want to dig into cardiologist overread accuracy, or initial findings, etc.
I’m hoping to have a proposed vocabulary posted to OHDSI by the end of the year to cover the above commercial measurements and criteria - including my own. Let me know what ECG devices and management system you are using - I may already have an OMOP mapping and software worked out.
Best - MK