An endothelial cell that lines the intracavitary lumen of the heart, separating the circulating blood from the underlying myocardium. This cell type releases a number of vasoactive substances including prostacyclin, nitrous oxide and endothelin. [ GOC:tfm ISSN:0452-3458 ]
Synonyms: endothelial cell of endocardium endocardial endothelial cell