Endocarditis (endo = within + card = heart + itis - inflammation) is a reaction to trauma of the inner membrane of the heart and the heart valves. This trauma is usually due to a viral or bacterial infection or the result of toxins produced by viral or bacterial action in another part of the body.
If only a heart valve is inflammed then the word would be "Valvulitis" preceded by the valve name (tricuspid valvulitis).