Heart failure

If you have symptoms of heart failure, your doctor will ask you to describe them in some detail, and you will also have a physical examination.

If your doctor thinks you may have heart failure, you will probably need to have tests to find out more. These might include:

• Blood tests, to check if there is anything in your blood that might indicate heart failure or some other illness.
• A chest X-ray to check whether your heart is bigger than it should be, and that there is no fluid in your lungs, which might indicate heart failure.
• An electrocardiogram (ECG), which records the natural electrical activity in your heart.
• An echocardiogram (an ‘echo’), which checks how well your heart is pumping.

Blood and urine tests can show whether you have another condition that may be causing your symptoms, such as anaemia, diabetes, thyroid problems or kidney disease. A blood test can also check whether the level of cholesterol (fat) in your blood is too high, as this can be a sign of coronary heart disease, which may lead to heart failure.

BNP test
Some doctors send a blood sample off to be tested for a substance called brain-type natriuretic peptide (BNP), which is found in the blood as well as in the brain where it was originally discovered.

A damaged or overworked heart will leak BNP into the blood, and the BNP test can detect these higher levels. The test can also indicate the severity of your heart failure. Higher levels of BNP in the blood can mean that you have more severe heart disease, while lower levels indicate a milder form. Some hospitals use a slightly different version of the test, called the NTproBNP. But because BNP testing is new and there is some debate about how best it can be used, not all hospitals use it.

Want to know more?

• BNP test.

A chest X-ray lets doctors look inside the chest, at the heart and lungs. If you have symptoms of heart failure, such as shortness of breath, a chest X-ray can help find out whether your symptoms are caused by heart failure or a lung condition. If the results of your X-ray indicate that you may have heart failure, you will probably need to have other tests, such as an electrocardiograph or echocardiogram.

Want to know more?

• X-rays.

An electrocardiogram is a test that measures the electrical activity of the heart. It can detect problems with the way the heart beats (rhythm) and check if you have had a heart attack in the past that you were perhaps unaware of.

During the test, self-adhesive electrodes are attached to the skin on the arms, legs and chest. Some areas may need to be shaved. The test is painless, and takes less than a minute to carry out once the electrodes are in place. The electrodes are then removed, and the doctor will review the ECG trace on a computer or paper print-out.

Sometimes you may need a slightly different type of ECG test. These include:

24-hour ECG recording (sometimes called Holter monitoring or ambulatory ECG)
In this test, the ECG is recorded over 24 hours. The electrodes are attached to your chest, and the wires attached to these electrodes are connected to a small portable tape recorder, which is worn on a belt around your waist. The test is useful because it shows changes in your heart’s rhythm (palpitations) that may occur only sporadically.

Exercise ECG (sometimes called an exercise stress test)
This is an ECG that is recorded while you are walking on a treadmill or cycling on an exercise bike. It records how your heart copes when it has to work harder during exercise.

If your ECG and the results of your blood tests or X-ray are abnormal, then you are more likely to have heart failure. However, it does not mean that heart failure is definitely causing the symptoms. Your doctor will probably want you to have an echocardiogram to decide for sure.

Want to know more?

• British Heart Foundation: ECG.

The test that decides for sure whether or not you have heart failure is an ‘echo’ test (a shortening of echocardiogram). An echocardiogram is painless. A pulse of harmless, high-frequency sound waves is passed through the chest wall, and these ‘bounce back’ from the structures in the heart (in a similar way to an ultrasound scan in pregnancy.

For the test, you will be asked to lie on your left side with your left arm behind your head. Lubricating jelly is put on your chest, and the ultrasound probe (recorder) is placed at various points on the chest between the ribs. The probe picks up echoes from the heart and shows them on the screen as a detailed picture (echocardiogram) of the structures of the heart.

The test allows the operator to find out a lot of information about the heart, including:

• How well the valves are working, and whether any of them are damaged.
• How well the heart is working as a pump (i.e. systolic function – when the beat or contraction of your heart forces blood to circulate around the body).
• How well the heart relaxes after pumping (i.e. diastolic function – when the heart relaxes after each beat or contraction, allowing it to fill with blood).
• Whether there are holes in the walls between the chambers of the heart, disrupting the one-way system of blood flow and allowing blood to flow from one side to the other (intracardiac shunts).

The most important finding from an echocardiograph is usually a measurement of how well one of the chambers of your heart – the left ventricle – is pumping. The left ventricle pumps the blood around the body. The wall of the left ventricle is normally much thicker than the wall of the right ventricle, because the right ventricle only pumps blood to the lungs and back.

This measurement, called the left ventricular ejection fraction (LVEF), is an estimate of how much of the blood that enters the left ventricle is pumped out when the heart muscle beats (contracts). In a healthy heart, about 60% of the blood entering the left ventricle gets pumped out when the heart muscle contracts. So a normal LVEF would be around 60%. A value of less than 40% would indicate that the heart is not pumping well.

Sometimes different types of echocardiogram are performed. These include:

Stress echocardiogram
This is an echocardiogram that is carried out to see how the heart functions when it has to work extra hard. It is performed by increasing the person’s heart rate, either by exercise on a treadmill or exercise bike, or by special medication.

Transoesophageal echocardiography
This test is carried out when doctors need to look at your heart valves in more detail. Pictures of your heart are taken from inside your body, by passing a small probe mounted at the end of a thin flexible tube down your oesophagus (the tube that connects your mouth to your stomach). Before the test, you may be given a mild sedative to help you relax, and an anaesthetic will be sprayed on the back of your throat to make you more comfortable. While the probe is in your oesophagus, pictures of your heart are taken. The probe is then gently withdrawn.

Want to know more?

• British Heart Foundation: echocardiograms and tests for heart conditions (PDF).

Most people with heart failure will have problems with the left ventricle and will therefore have a low LVEF. Other people may have problems with the heart relaxing after it pumps, or problems with one of the heart’s four valves.

Finding out exactly what is causing heart failure is important, as treatment is different for each type.

Want to know more?

• British Heart Foundation: heart failure and problems with heart valves.