Computational technologies have been increasingly explored to make biomedical knowledge and data more accessible for human understanding, comparison, analysis and communication. In this context, ontology has been recognized in the bioinformatics literature as a suitable technique for advancing knowledge and data representations in Biomedicine. Moreover, automated reasoning and visualization mechanisms can favor in providing support for human comprehensibility as well as in dealing with the complexity inherent to this domain. This paper elaborates on the application of ontology for heart electrophysiology representation, reasoning and visualization on the web. The ontology-based application we propose can be used to offer support for interactive learning in heart electrophysiology. Categories and Subject Descriptors H.3.5 [Information Storage and Retrieval]: Online Information Services – Web-based services; I.2.1 [Artificial Intelligence]: Applications and Expert Systems – Medicine...