Coronary heart disease is associated with age and is a lifelong condition that affects many people.

Coronary arteries are like small pipes that supply blood to your heart. They get narrower when fatty material gradually builds up inside and clogs them.

The fatty material is called plaque. The process of plaque building up is called atherosclerosis. This can start when you are young and may be well advanced by middle age.

Stable plaque is generally not harmful but if it narrows the arteries too much, they may sometimes not deliver enough blood to your heart. The first effects of this are pain and discomfort called angina. Angina needs to be treated. 

Unstable plaque has more fat, a thin cap and is inflamed. It may not severely narrow the artery, but it can develop a crack on the surface, exposing the contents of the plaque to the blood. Blood cells try to seal the gap in the surface with a blood clot. The blood clot partially or completely blocks the artery.

 A heart attack occurs when a blood clot completely blocks the flow of blood and seriously reduces blood flow to the heart muscle. 

If you have had a heart attack, you have coronary heart disease.