Your heart is a muscle about the size of your fist. It pumps blood around your body to keep you alive.
Blood flows to and from the heart through tubes called arteries.
The heart gets its own supply of blood through tubes on the heart’s surface. These are called coronary arteries.
Sometimes blood cannot flow properly through these tubes to the heart because fatty substances block them.
This is known as coronary heart disease.
Coronary heart disease is a big cause of death.