Patient Information

There are many different tests we can do to see how the heart is functioning. Which test we recommend depends on what your symptoms are. The British Heart Foundation website ( is a good source of information for more details, but here are some of the commonly performed heart tests.

Stress Echocardiography

Stress echocardiography (often called ‘stress echo’) is a widely used test to assess how well the heart is working. An ultrasound machine is used to take pictures of the heart at rest and after the heart rate has been increased (the ‘stress’), either after exercise (walking on a treadmill) or after a drug has been given to increase the heart rate in a gradual and controlled manner. The ultrasound images of the heart at rest and at stress are then compared with one another to see how well the heart copes with the extra workload. The test is safe, painless, doesn’t involve exposure to any radiation and takes about 30 minutes.

Stress echo is most commonly used in patients experiencing chest pain to look for coronary heart disease. The chest pain may be a sign that the heart is not getting enough blood when it needs it – often referred to as angina – and stress echo can detect this. Stress echo can also be used to check how well the heart works in patients with valve disease (e.g. narrow or leaky heart valves) and in patients with heart failure also.

Northwick Park Hospital performs more than 2000 stress echo tests each year and this is more than any other hospital in the country.


An echocardiogram (or “echo”) is a non-invasive and diagnostic test that uses sound waves (ultrasound) to create video pictures of the heart so that the structure, movement and function of the heart’s chambers and valves can be assessed. The technology is similar to that used to assess a baby’s health during pregnancy.

This enables the doctor or technician to diagnose many types of heart muscle and valve disease, follow the progress of disease over time, to plan medical and surgical treatment, and to evaluate the success of this treatment.

There are two main types of echocardiogram:

1) Transthoracic echocardiogram: this is the most common type of echo where the hand held ultrasound device is placed over several parts of the chest. This is safe and painless with the entire procedure taking less than 30 minutes.

2) Trans-oesophageal echocardiogram (TOE): this involves placing a small ultrasound probe into the gullet. The gullet is located very close to the heart. This means that the heart can be viewed and assessed in even greater detail.

The latest technology allows us to view the heart in three-dimension (3D) using echo. It’s almost as if the doctor is looking at the heart with his own eyes!

We perform around 6000 scans a year making this department one of the busiest in the country.

ECG & Exercise ECG

An ECG (Electrocardiograph) is a recording of the electrical activity of the heart and gives us a picture of the rhythm of the heart and is useful in helping diagnose a heart condition.

As frequently heart symptoms first start to show initially when exercising, it will sometimes be helpful to record this when exercising on a treadmill or exercise bike.

Angiography & Angioplasty with Stenting

An angiogram is when an image of the arteries supplying the heart muscle itself is taken. A small tube is inserted into the heart via an artery in the arm or leg. Dye is then injected and using X-ray the outline of the artery is recorded. If a narrowing is found, if possible a wire is placed across the narrowing and then a balloon is passed over this wire and inflated to re open the artery. Finally, a stent, which is a scaffold, is inserted to help keep the artery open.

Tablets have to be taken for a year after this procedure to reduce the clotting mechanism of the blood and prevent the stent becoming blocked. If there are numerous blockages or if this procedure is unable to be performed, patients may be referred for a bypass operation.