What is meant by coronary heart disease?

CAD:CHD: Coronaries are the arteries that irrigate the muscle of the heart. An obstruction by a clot or plaque of cholesterol in them will lead to a hear attack. The hear may have other diseases like "valvular disease" ( diseases of the valves), "cardiomyopathy"( disease of the heart muscle). So coronary disease is not the only thing that can affect the heart.

It refers to any : Disease of the coronaries, whether congenital or acquired. In the usual parlance, it refers to blockage of the coronaries that developed in time although has genetic overtones.