Congestive Heart Failure

Authored by , Reviewed by Dr John Cox | Last edited | Meets Patient’s editorial guidelines

Heart failure does not mean that your heart has stopped or is going to stop at any minute. It means that your heart is not functioning as well as it should. Heart failure can be caused by many different conditions. Symptoms include fluid retention, breathlessness and tiredness. Medication can usually ease symptoms and can often improve the outlook.

What is heart failure?

Dr Yassir Javaid

In a normal healthy heart, during each heartbeat a set amount of blood enters the heart and is pumped out again. If you have heart failure, your heart cannot cope with pumping the full amount of blood in each heartbeat.

Heart failure is divided into types according to how suddenly it has come on. It is called acute heart failure if it has made you unwell quite suddenly. If the symptoms have been going on for some time, it is called chronic heart failure. As a general rule, you will often be admitted to hospital if you have acute heart failure, whereas if you have chronic heart failure you will probably have tests done as an outpatient. If you have chronic heart failure, it is possible to develop acute heart failure if matters suddenly become worse.

Heart failure is also divided into types depending on how much blood the heart manages to pump out in each heartbeat. The term ejection fraction means the amount (percentage or fraction) of the blood in the biggest chamber of the heart (the left ventricle) that is pumped out (ejected) with each heartbeat before it fills up again for the next beat. It is normal for some of the blood to be left behind with each beat but usually at least half the blood is pumped out with every beat. If less than 40% of the blood is pumped out, this is called heart failure with reduced ejection fraction. If more than 40% is pumped out, it is called heart failure with preserved ejection fraction. Distinguishing between the two is important as it will affect the treatment which is used.

For further information about the heart itself, see the leaflet called Anatomy of the heart and blood vessels.

Symptoms of heart failure can vary. The most common symptoms are:

  • Feeling breathless. This may occur when you exert yourself, when you lie flat, or even wake you when you are asleep.
  • Retaining fluid. Most commonly this shows as swollen ankles. It can also cause swelling of your legs, bottom or tummy.
  • Feeling tired

Other symptoms include:

  • Having a cough.
  • Feeling light-headed or dizzy or having fainting spells.
  • Losing your appetite.
  • Constipation.

Depending on the underlying cause for the heart failure, you may also have other symptoms. For example, chest pains if you have angina, the sensation of having a 'thumping heart' (palpitations) if you have a heart rhythm problem, etc.

The severity of heart failure is often graded into four classes or stages:

  • Class 1 (very mild) - ordinary physical activity does not cause breathlessness, extreme tiredness (fatigue), or palpitations. You may not have any symptoms at all. However, tests (perhaps done for other reasons) may have detected mild heart failure.
  • Class 2 (mild) - you are comfortable at rest. However, ordinary physical activity such as walking causes some breathlessness, fatigue, or palpitations.
  • Class 3 (moderate) - although comfortable at rest, slight physical activity such as dressing yourself causes breathlessness, fatigue, or palpitations.
  • Class 4 (severe) - you are unable to carry out any physical activity without developing breathlessness, fatigue, or palpitations. Symptoms are often present even at rest. With any physical activity you have increased symptoms and discomfort.

About 920,000 people in the UK currently have heart failure.There are around 67,000 admissions to hospital for heart failure in England and Wales each year. Heart failure becomes more common as people become older. It is commonly diagnosed in people in their 70s. In the UK around one in seven people aged 85 or more have heart failure. In people aged 65-74, around one in 35 have heart failure. 

Heart failure is not an exact term. Heart failure is a general umbrella term and may develop as a complication of various conditions. Conditions that cause heart failure affect the ability of the heart to function well as a pump. Conditions that may cause heart failure include the following:

Coronary heart disease (CHD) is the most common, or main, cause of heart failure. In particular, heart failure may develop after a heart attack (myocardial infarction). See the separate leaflets called Angina and Heart Attack (Myocardial Infarction) for more details.

Other causes

Various other conditions can also cause heart failure - for example:

Sometimes the cause of heart failure is not known.

The cause will often have an effect on the type of heart failure (eg, reduced or preserved ejection fraction), the treatment, and whether or not it can be cured.

When a doctor examines you, he or she may find signs that occur with heart failure - for example:

  • An enlarged heart.
  • A faster than normal pulse.
  • Signs of fluid retention (such as swollen ankles, an enlarged liver or crackles in the lungs when the chest is examined).

However, these signs and the symptoms mentioned above can be due to various conditions other than heart failure. If heart failure is suspected, tests are usually done to confirm the diagnosis. A blood test is usually done to measure a chemical called B-type natriuretic peptide (BNP) or N-terminal pro-B-type natriuretic peptide (NT-proBNP). BNP is a hormone that helps to keep blood volume at a steady level. These substances are increased in heart failure, and the higher they are, the more severe the heart failure is likely to be. However, they can be high in other conditions also. You will usually also have a 'heart tracing' (electrocardiogram, or ECG).

If your own doctor suspects that you may have heart failure then you are likely to be referred to a specialist heart failure clinic at a hospital. If you are very unwell (if you have acute heart failure), you would be sent to hospital straightaway. Otherwise you are usually referred to be seen by a specialist within 2 or 6 weeks, depending on how high your BNP level is.

The specialist heart failure team will arrange an ultrasound scan of the heart (echocardiogram). This painless test can usually confirm the presence of heart failure and can often diagnose the cause of the heart failure. It also will measure the ejection fraction explained above, to determine which type of heart failure you have. Other tests such as a chest X-ray, a urine test or other blood tests may also be advised to rule out other causes of the symptoms.


  • Diet. Weight should be within a healthy range (BMI 18.5 to 25). If you are overweight, try to lose weight to reduce the extra burden on your heart. If you are underweight, your specialist or GP may refer you to a dietician for advice about nutritional supplements.
  • Do not smoke. The chemicals in tobacco cause blood vessels to narrow, which can make heart failure worse. Smoking can also make CHD worse. You may benefit from being referred to a local 'stop smoking' clinic if you are finding it hard to stop smoking.
  • Exercise. For most people with heart failure, regular low-intensity exercise is advised. Exercise cannot reverse heart failure, but the fitter the heart, the better it will pump. The level of exercise to aim for will vary from person to person. Before you start to increase your exercise, get advice from your specialist, as some people with heart valve problems or more severe heart failure may not be able to do some forms of exercise. You may also be referred for a specialised heart failure rehabilitation programme which may include exercise.
  • Immunisation. You should have an annual influenza jab and be immunised against the pneumococcal germ (bacterium).
  • Weigh yourself regularly if you have moderate-to-severe heart failure. Your specialist will advise if you need to do this and if so, how often you should weigh yourself. If you retain fluid rapidly, your weight goes up rapidly too. So, if your weight goes up by more than 2 kg (about 4 lb) over 1-3 days, you should contact a doctor. You may need an increase in your medication.
  • Alcohol. You should not exceed the recommended amount of alcohol, as more than the recommended upper limits can be harmful.


The following medications are commonly used to treat heart failure. They will be tailored to the individual person, depending on the type, cause and severity of the heart failure.

Other medications are also used for some cases. For example, aspirin may be advised for people who have had a heart attack in the past. Anticoagulants may be advised for those who have had a clot in the past. Digoxin may be useful in some specific situations. Your specialist will be able to give you more information if you need additional medications.

Editor's note

Dr Sarah Jarvis, 1st March 2021

New drug option for some people with heart failure

The National Institute for Health and Care Excellence (NICE) has recommended a new option for some people with heart failure if muscle of their left ventricle (the biggest for the four chambers in the heart) is not pumping as well as normal.

Dapagliflozin has been used for some years to treat high blood sugar in people with type 2 diabetes. However, it has been found that dapagliflozin, and other closely related medicines, can also significantly improve heart failure in some people. 

For this reason, NICE has recommended that it can be prescribed under advice from a specialist if you still have symptoms despite taking several of the treatments above.

Note: it is very important that you take the tablets that have been prescribed for you. You should discuss with your doctor if you stop taking any of your tablets.

Devices for heart failure

Various devices are implanted in a small number of people with heart failure. Examples include implantable cardioverter defibrillators (ICDs) and pacemakers.

ICDs work by detecting any abnormal heart rhythms that may occur. If your heart rhythm is too slow, the device can give your heart extra support by working as a normal pacemaker. If your heart beats too fast, the ICD can give you a burst of extra beats at a slightly faster rate which should return your heart back to a normal rhythm, or it can give you a shock (defibrillation) to restore a regular heartbeat.

Pacemakers work differently. In some cases, there is some damage to the specialised heart cells that carry the signals needed for your heart to squeeze (contract) properly. This can then cause the signals to travel out of synch which leads to your heart pumping less forcefully and less efficiently. The pacemakers work to control these signals so the heart can then beat more effectively. This is also known as cardiac resynchronisation therapy.

These different devices have dramatically altered the treatment of heart failure in selected cases and have improved both the outlook and quality of life. However, these devices are only suitable for certain people with heart failure. Your doctor will be able to discuss with you in more detail if you are suitable for one of these devices.

Other treatments

As mentioned above, heart failure usually develops as a complication of various conditions. Other treatments for the underlying condition may be advised in certain cases. For example:

  • Treatment to lower blood pressure if you have high blood pressure (hypertension).
  • Treatments to slow down the progression of CHD if this is the cause of the heart failure. For example, lowering a high cholesterol level.
  • Surgery to replace or fix a heart valve may be done if a damaged heart valve is the cause of the heart failure.
  • A heart transplant is an option in some cases.

It is difficult to give an outlook (prognosis) for an individual. It depends on the cause of the heart failure, whether you have other medical conditions, and how severe it is. Speak to your specialist about your individual case. In general, the more severe the heart failure, the worse the outlook. In many cases, the symptoms remain at a stable level for quite some time (months or years) before becoming worse. In some cases, where there is a reversible cause, heart failure can get completely better. In some cases, the severity and symptoms become gradually worse over time. Sadly in some cases, heart failure can be fatal. About half of those diagnosed with heart failure die within five years of the diagnosis.

If symptoms become very severe, and are not responding well to treatment, this is known as 'end-stage heart failure'. In this situation, palliative care (often at home) from a team of different health professionals may be helpful. The priority in this situation is keeping the person comfortable, and alleviating symptoms as much as possible. A person diagnosed with end-stage heart failure is likely to die over the following 6 to 12 months.

Over recent years, various new treatments have been introduced which have led to a much improved outlook for people with heart failure. Studies are ongoing to establish which treatment options improve outlook the most.

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Further reading and references

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