The heart is a muscle about the size of your fist. It pumps blood around your body and beats approximately 70 times a minute. After the blood leaves the right side of the heart, it goes to your lungs where it picks up oxygen.
The oxygen-rich blood returns to your heart and is then pumped to the body's organs through a network of arteries. The blood returns to your heart through veins before being pumped back to your lungs again. This process is called circulation.
The heart gets its own supply of blood from a network of blood vessels on the heart's surface called coronary arteries.
What causes coronary heart disease?
Coronary heart disease is the term that describes what happens when your heart's blood supply is blocked or interrupted by a build-up of fatty substances in the coronary arteries.
Over time, the walls of your arteries can become furred up with fatty deposits. This process is known as atherosclerosis and the fatty deposits are called atheroma.
Atherosclerosis can be caused by lifestyle factors and other conditions, such as:
Coronary heart disease (CHD) is the leading cause of death both in the UK and worldwide.
It's responsible for more than 73,000 deaths in the UK each year. About 1 in 6 men and 1 in 10 women die from CHD.
In the UK, there are an estimated 2.3 million people living with CHD and around 2 million people affected by angina (the most common symptom of coronary heart disease).
CHD generally affects more men than women, although from the age of 50 the chances of developing the condition are similar for both sexes.
As well as angina (chest pain), the main symptoms of CHD are heart attacks and heart failure. However, not everyone has the same symptoms and some people may not have any before CHD is diagnosed.
CHD is sometimes called ischaemic heart disease.