Do the PromoCell HCMEC represent the endocardial cells, i.e. those lining the ventricles? If so, why are they referred to as microvascular endothelial cells?

Our HCMEC (Human Cardiac Microvascular Endothelial Cells) are not endocardial cells. They are isolated from the capillaries in the heart muscle. Therefore, they are in fact microvascular.