coronary heart disease

Why do many people say ‘coronary heart disease’, as the word ‘coronary’ itself means pertaining to heart?
Is this usage correct?

Coronary heart disease is a name applied to any heart disorder caused by disease of the coronary arteries.

Thank you. So in this conext it is a very specific term meaning not just heart alone, but arteries of the heart.

Yes-- but some people may use the phrase without knowing that.