Summary Objective of the Paper: To find ways to meet the need for specifying terminology and developing a format to describe knowledge in specific subject areas (SA) that will be effective, easily-accessible and clear for both people and programs. This is related to terms, their relationships, models of ECG devices, filters, etc. Key Points: The use of ontology facilitates the following: - a repeated use of knowledge in SA; - a differentiation of the knowledge related to SA from operational knowledge; - a shared general understanding of the information structure among people and programs. An ontology carefully developed for one SA can then be used in other SAs. Moreover, several existent ontologies describing some subdomains of a large SA can be integrated when it is required to create a big ontology. Conclusion: Any SA can have countless ontologies, as each new ontology is just another way to structure concepts and their relationships. Modern doctors must be able to use medical information technologies in their everyday practices, which help them to not waste time on routine calculations and save time and energy for solving current problems. Keywords: electrocardiogram (ECG), telemedicine, ontology, SCP-ECG, OWL.