Heart failure basics: what the term means and how it is managed

The NHS puts it simply: heart failure is when the heart cannot pump blood properly. The US National Heart, Lung, and Blood Institute (NHLBI) describes a condition in which the heart does not pump enough blood for the body's needs, and states that the term does not mean the heart has stopped. It can come on suddenly or develop gradually, and it can affect one or both sides of the heart.

There is no cure at present, but the NHS and the NHLBI both say treatment and lifestyle changes can help people have a better quality of life. With treatment, the NHS says, the condition can stay stable for many years. For the basics of the pump itself, see how the heart works.

Heart failure is usually the end result of another condition that damages or strains the heart. The NHLBI lists coronary heart disease, heart inflammation, high blood pressure, cardiomyopathy (disease of the heart muscle) and irregular heartbeat. The NHS adds heart valve disease, chronic kidney disease, anaemia and thyroid problems, and says risk is higher with age 65 or over, overweight or obesity, smoking and heavy drinking.

Two of these have their own pages: high blood pressure strains the heart over time, and a leaking or narrowed valve can do so too, as described in heart valve problems.

The pattern differs by region. A 2025 scoping review in BMC Cardiovascular Disorders says heart failure in sub-Saharan Africa has causes including hypertension, rheumatic heart disease, cardiomyopathies and infections, differing from high-income countries. It cites pooled figures of 39.2% for hypertensive heart disease, 21.4% for cardiomyopathies and 14.1% for rheumatic heart disease. These come from studies that vary in size and setting, so they are best read as a rough guide. Rheumatic valve damage is explained in rheumatic heart disease.

The NHLBI notes heart failure may not cause symptoms right away. The NHS lists the usual features:

• breathlessness during everyday activities or when lying down
• weakness, tiredness or light-headedness
• swelling in the feet, ankles, legs or abdomen, or feeling bloated
• sudden weight gain
• coughing at night, or coughing up frothy pink phlegm

Symptoms can vary from day to day, according to the NHS.

A doctor starts with symptoms, medical and family history and a physical examination. From there the NHS says tests may include blood and urine samples, an ECG, a chest X-ray, an echocardiogram (echo, an ultrasound scan of the heart) and an MRI scan. The NHLBI names a blood test for brain natriuretic peptide (BNP), a molecule measured in the blood, and says echo or other imaging is used to measure the ejection fraction, the share of blood pumped out of the heart with each beat.

Care is built around the cause and the type of heart failure. The NHLBI describes several groups of medicines: those that remove extra sodium and fluid, those that relax blood vessels, and those that slow the heart rate. Which medicines suit which person, and in what amounts, are decisions for the treating team.

Devices and procedures are used in some people. The NHLBI mentions biventricular pacemakers, implantable cardioverter defibrillators (which correct dangerous rhythms) and mechanical heart pumps, with transplant considered when other treatments have not worked. The NHS says everyone diagnosed should be offered cardiac rehabilitation.

Everyday habits count as well. The NHLBI advises lowering sodium (salt) intake, since salt may worsen fluid build-up, and it says people may be asked to limit salt and fluids; it gives no general amounts, so the advice comes from the clinician. Our page on salt and heart health explains the background. Taking medicines as prescribed, staying active as advised and avoiding smoking are also recommended.

The NHLBI says to watch for new or worsening symptoms and notes that weight gain, ankle swelling or increasing shortness of breath may mean fluid is building up. It advises asking the care team how often to check weight, when to report changes and when to get emergency care.

The NHS says to see a doctor if you have any symptoms of heart failure, and to seek an urgent appointment or phone the health line if you are breathless lying down or during everyday activity, are coughing up frothy pink phlegm or have suddenly gained weight. Severe breathing difficulty, pale, blue or grey lips or skin, or collapse needs emergency help. Emergency numbers differ by country, so use your local emergency number and do not drive yourself.

Heart failure means the heart is not keeping up with the body's needs, not that it has stopped. It follows conditions such as high blood pressure, coronary disease, valve disease and cardiomyopathy, and sources describe a somewhat different mix of causes in sub-Saharan Africa. Tests such as echo and BNP confirm it, and treatment combines medicines, devices where needed and daily habits guided by a clinician.