Heart failure

Heart failure is when the heart loses its ability to pump blood efficiently through your body. Find out the causes and symptoms.

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What is heart failure?


Oxygen and nutrients in blood provide your body with the energy it needs to operate normally, and if the heart does not pump these to your vital organs – they will cease to operate normally.

Heart failure may affect the left, right or both sides of the heart.

  • If the left half of the heart fails (left ventricular failure), fluid will build up in the lungs due to congestion of the veins in the lungs.
  • If the right half of the heart fails (right ventricular failure), general body vein pressure will increase and fluid will accumulate in the body, especially in the legs and in the abdominal organs, with the liver most likely to be affected.

    Often left heart failure when long-standing leads to right heart failure, causing biventricular failure (failure on both sides).

    What causes heart failure?

    Heart failure can be caused by many different diseases. Some of which happen as an acute, sudden effect, while others are chronic, long-term conditions.

    • High blood pressure.
    • Excess alcohol; this is quite a common cause of heart failure, either by itself, or by worsening another pre-existing condition.
    • Diseases of the heart valves.
    • Ischaemic heart disease – a blood clot in one of the coronary arteries can cause injury and irreversible damage to the heart muscle, usually during an acute heart attack. However, surprisingly, this can also happen gradually. Sometimes the blood supply fails slowly, and the heart shuts down its metabolism so that it doesn't pump well, but still stays alive. It's important to detect this phenomenon of hibernation, as replumbing the heart blood vessels can result in dramatic improvement in heart function.
    • Cardiomyopathy (chronic heart muscle disease). This is increasingly recognised as an important cause of heart failure. In many – but not all – cases, there is a strong genetic basis. This means that if one member of a family is diagnosed as having cardiomyopathy, often all other close family members should be screened for this.
    • Heart rhythm disturbances; though these can complicate heart failure, in a few cases heart rhythm disturbances can cause heart failure. These are ones where the heart goes too fast for several months, usually with heart rates above 140 beats per minute. Treating the rhythm disturbance can totally reverse the heart failure.
    • Congenital heart diseases.
    • Endocrine disorders, including decreased metabolism due to abnormal thyroid function (rare) and also increased metabolism due to abnormal thyroid function (rare).
    • Severe anaemia (rare).

      What are the symptoms of heart failure?

      Left-sided heart failure

      • Shortness of breath together with a reduction in mobility. If present, at rest they are markedly worse on lying down in bed at night, so that patients start to prop themselves up with extra pillows, or even start sleeping in a chair.
      • In less severe cases, breathing problems only start upon exertion.
      • A dry cough may develop that doesn't go away.
      • Fatigue.
      • Muscle weakness.
      • Weight loss, usually only in advanced cases.

        Right-sided heart failure and biventricular failure

        • Swelling in the legs (oedema).
        • Oedema may lead to dry skin on the lower part of the legs because of pressure from inside the tissue.
        • There may be an eczema-type rash on legs, which can be complicated by ulcers that do not heal (venous leg ulcers).
        • Possible accumulation of fluid in the abdominal cavity and organs, especially the liver. The organs swell and the abdominal wall might expand.

          How does the doctor diagnose heart failure?

          • The diagnosis is usually based on medical history combined with an examination that will look for an increased heart rate, abnormal heart sounds, the presence of heart murmurs, swollen legs, fluid in the lungs, swollen neck veins and liver enlargement.
          • To determine the extent of the heart failure, a chest X-ray is done. This often shows a large heart regardless of the cause, and may show fluid in the lungs. Most large hearts on chest X-Rays however are not due to heart failure, but are due to fat around the heart in larger people. This fat does not interfere with the function of the heart.
          • To establish whether a previous heart attack may be associated with the development of heart failure, an electrocardiogram (ECG) will be taken. The ECG is almost always abnormal in heart failure, and can often give a clue to the cause of the heart failure
          • Blood samples taken to check for metabolic upset and kidney function. There is a blood test for heart failure, called the BNP (brain natriuretic peptide) test. When this test is normal, heart failure is excluded. The more abnormal it is, the more likely heart failure is to be present. It can be used to diagnose heart failure, and follow up its response to treatment.

            To find out what caused the heart failure, further investigations are required.

            These can include:

            • additional blood tests to check for recent viral infections and for rare metabolic causes of heart failure (for example, a genetic illness whereby iron is stored to excess in the heart, so causing damage)
            • an ultrasound examination of the heart (echocardiograph); this should be carried out in all cases of suspected heart failure. It can help confirm the diagnosis, and also the cause. Knowledge of the cause of heart failure is crucial to treatment
            • an exercise test using a treadmill, or a special nuclear test, to investigate the possibility of heart artery narrowing
            • an examination of the coronary arteries by injecting a dye into the left and right coronary arteries so any blockages show up on an X-ray, (an 'angiogram' test) – this is almost always done, but may not be necessary if the patient is very young (say, less than 30 years old)
            • measurement of pressure and valve function in between both the chambers of the heart and the great blood vessels (cardiac catheterisation)
            • taking a small sample of heart muscle (biopsy) if heart muscle disease (cardiomyopathy) is suspected at the time of catheterisation. This is now only very rarely done
            • additional non-invasive imaging to look at the heart muscle using magnetic resonance imaging (MRI). This is increasingly used, as the MRI scan is a very accurate test both in finding the cause of heart failure and in assessing its severity
            • tests for the electrical stability of the heart, including heart rate monitors that are worn for 24 hours ('24-hour ECG, otherwise known as the Holter test).

              In the long term

              Heart failure is a progressive disease, with the potential for deterioration, which may be gradual, though distressingly in some cases can be quite sudden, for example, if a heart rhythm disturbance occurs.

              It's a serious illness, with the potential to substantially lessen life expectancy.

              On average, the life expectancy of patients with heart failure is worse than that of patients with cancer, though there are many exceptions.

              Treatment can often slow the progression of the illness and substantially increase your quality of life.

              What are the signs of deterioration?

              Left-sided heart failure
              • Increasing difficulty in moving around.
              • Breathlessness at rest or when lying flat (orthopnoea).
              • Waking up at night with breathlessness (paroxysmal nocturnal dyspnoea).
              • A cough with frothy sputum (lung oedema).
                Right-sided heart failure
                • Venous leg ulcers.
                • General swelling of the legs, abdomen and, in men, the scrotum.
                • Possible liver enlargement if severe.

                  What can the doctor do?

                  • Investigate with a view to coronary artery widening or bypass (revascularisation) and valve surgery replacement if necessary.
                  • Treat any obvious causes of heart failure.
                  • Give advice regarding risk factors such as smoking, excessive weight and high blood pressure.
                  • Refer you for further investigation to identify the cause of the heart failure. For example, an overactive thyroid, excess alcohol, or too-high heart rate from a heart rhythm disturbance.
                  • Prescribe medication.
                  • Monitor your health on a regular basis.

                    Which medication is used afterwards?


                    Aspirin (eg Nu-seals 75mg) is prescribed to patients who have narrowed arteries unless it can't be tolerated. It has a mildly blood-thinning effect and goes some way to prevent further cardiac events. Aspirin must be taken for the rest of your life.

                    Clopidogrel (Plavix) can be given instead of aspirin.

                    Agents for increasing cardiac function

                    Digoxin (eg Lanoxin) helps the heart contract more vigorously.

                    Nitroglycerin and other nitrates

                    Nitrates such as glyceryl trinitrate or isosorbide mononitrate (eg Imdur) make the veins and arteries relax and widen (dilate). When the blood vessels dilate in this way there is more space inside them and so less resistance. This makes it easier for the heart to pump blood around the body.

                    Beta blockers

                    Beta blockers block the action of adrenaline hormones on the heart. They reduce the energy used by the heart to pump blood around the body, so it doesn't have to work so hard. They are very useful in reducing symptoms from heart failure and also in extending life expectancy. If patients have asthma, they cannot take beta-blockers, in which situation they can use the equally effective drug called ivabradine.

                    ACE inhibitors

                    ACE inhibitors prevent the formation of a hormone that makes the blood vessels contract. This means that less effort is needed by the heart to pump blood. A side effect of ACE inhibitors is cough; in this situation, patients can use the equally effective class of drugs known as angiotensin receptor blockers. They reduce symptoms and prolong life.


                    Diuretics help the body excrete excessive fluid and salts, reducing the strain on the heart and blood vessels. If you take diuretics, you may need to take a potassium supplement because some diuretics cause a loss of potassium. A diuretic called eplerenone is very useful in conserving potassium and also extending life expectancy.


                    Warfarin will be used to prevent stroke in those with heart failure and a rhythm disturbance called atrial fibrillation.


                    There are several sorts of pacemakers that are often used in patients with heart failure.

                    • Pacemakers to speed up a slow heart; these are rarely used. None-the-less, sometimes heart failure is due to damage to the electrics of the heart wherein the top part of the heart fails to communicate electrically with the bottom part. This results in a very slow heart rate, and heart failure. A pacemaker may be curative in this situation.
                    • Pacemakers to slow down a fast heart rate; most fast heart rates in patients with heart failure are slowed down using drugs, particularly beta-blockers. However, some patients with damaged hearts can have episodes where there heart suddenly races far too fast; some of these episodes are so fast that the heart effectively stops beating, and unless treated immediately, the patient will die. There are complicated pacemakers, known as implantable cardiovertor defibrillators (ICD) that can detect too fast heart rates, and treat them either by pacing the heart quickly, or by discharging a large internal electric shock to the heart, which effectively stops the heart, and then it restarts in the normal heart rhythm. These devices are used in patients who have had these dangerous rhythm disturbances, or who are at high risk of having them. Your doctor should always assess if you would benefit from such a device. They do not improve heart function, but they do prolong life expectancy.
                    • Pacemakers to make the heart pump more efficiently; in some patient with heart failure the electrics of the heart is so damaged that different parts of the main chamber pump at widely differing times, instead of altogether at the same time. In this situation, the pumping function of the heart is very inefficient, and this can cause or exacerbate heart failure. Implanting a pacemaker that stimulates all the different parts of the heart to pump together can be a very effective means of improving heart function, so lessening symptoms and prolonging life. Such a pacemaker is called a cardiac resynchronisation therapy device CRT.
                    • An ICD can be combined with a CRT device; these are the most sophisticated pacemakers.

                      What can be done to avoid heart failure?

                      • Stop smoking.
                      • Avoid overeating and ensure that you are not overweight.
                      • Exercise regularly.
                      • Eat a healthy, balanced diet.
                      • Do not add salt to your food.
                      • Do not drink more than the recommended level of alcohol.
                      • If you are suffering from a disease that can cause heart failure, such as high blood pressure, it is important to have it treated as soon as possible. The risk of developing heart failure will then be greatly reduced.
                      • If you need help with any of the above, contact your GP for advice.

                        Based on a text by Dr Sabine Gill, Dr Steen Dalby Kristensen

                        Last updated

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