There are a number of risk factors for coronary heart disease, some of which are within your control.

Risk factors you cannot change

Age: CHD is more common as people get older.
Family history: CHD can run in families, meaning that if lots of people in your family have had CHD, then your risk is increased. This is usually due to a combination of several genes and also habits that are common amongst the whole family. In some families, just one single gene may be altered and that can increase CHD on its own. 
Ethnicity: CHD is more common in South Asian and Black ethnic groups in the UK.

Risk factors you can do something about

High blood pressure: high blood pressure can often be controlled by making changes to your lifestyle, although many people also need medication. Your healthcare team can advise on your blood pressure goal and treatment.
High cholesterol: eating a healthy diet, maintaining a healthy weight and doing physical activity can all help bring cholesterol down, but people are often advised to take cholesterol tablets (such as statins) in addition if they are at high risk. Your healthcare team will measure your cholesterol and advise on treatment.
Living with overweight: living with overweight is strongly linked to CHD but the good news is that losing weight helps reduce many of the risk factors.
Being physically inactive: increasing physical activity can reduce the risk of developing CHD by as much as a third.
Smoking: chemicals from cigarettes cause a build up of fatty material in the walls of the arteries, causing CHD. Your healthcare team can support you in giving up smoking.
Having type 2 diabetes: diabetes damages blood vessels, increasing the risk of CHD. Controlling blood sugars reduces the risk of all forms of cardiovascular disease, including CHD.

How is coronary heart disease (CHD) diagnosed? 

If you are having symptoms that may be due to CHD, you should see your doctor who will talk to you about those symptoms and examine you. 

Alternatively, you may be called in to your GP surgery either for a routine health check or if there is a strong history in the family of CHD at a young age. 

Your doctor may arrange tests such as; 

ECG (electrocardiogram)

a recording of the electrical activity of the heart

Echocardiogram

a heart scan to look for any problems with the structure of the heart and heart valves. An echocardiogram is similar to the ultrasound scan that pregnant women have

Chest X-ray

to look for any lung conditions which might be an alternative cause of your symptoms

You might also be referred to the heart specialists (cardiologists) who can do more specialist investigations and scans of the heart. 

Keep your heart healthy leaflet