Heart Failure
Heart Failure: Symptoms, Causes & Treatment
Heart failure overview
Heart failure means the heart is not pumping blood around the body as well as it should, or cannot fill properly, so the body does not get the blood and oxygen it needs and fluid can build up in the lungs, legs and abdomen. It does not mean the heart has stopped or is about to stop. It is a long-term condition that can usually be treated, and with modern medicines many people feel much better and live well for many years.
Heart failure is common in the UK, and becomes more frequent with age. Its most frequent causes are coronary artery disease and previous heart attack, high blood pressure, heart valve disease, cardiomyopathy and heart rhythm problems such as atrial fibrillation. Diabetes, obesity, kidney disease, heavy alcohol intake and some cancer treatments also contribute.
How heart failure is classified (2026 European Society of Cardiology guideline)
The 2026 ESC heart failure guideline simplifies the way heart failure is grouped. Rather than three categories, it now uses two phenotypes, based on the pumping strength (ejection fraction) measured on an echocardiogram:
Heart failure with reduced ejection fraction (HFrEF) – the heart muscle is weak and pumps less blood with each beat.
Heart failure with preserved ejection fraction (HFpEF) – the heart pumps normally but the muscle is stiff and does not relax and fill properly. This is now the more common form, particularly in older people and in those with high blood pressure, diabetes or obesity.
There are four stages (A to D) for heart failure, from being at risk of heart failure (A), through structural heart changes without symptoms (B) and symptomatic heart failure (C), to advanced heart failure (D).
Recognising the earlier stages matters because treatment can prevent progression.
Your cardiologist will identify which type you have and, just as importantly, why you have it, because treating the cause is part of treating the heart failure.
Heart failure symptoms and signs
Heart failure symptoms can develop suddenly or gradually over months. They are caused by a combination of reduced blood flow to the body and fluid backing up behind the heart. Early symptoms are easy to put down to age or lack of fitness, so many people are diagnosed later than they could be.
Breathlessness
Breathlessness on exertion, such as climbing stairs or walking uphill, which gradually reduces how far you can walk
Breathlessness when lying flat, needing extra pillows to sleep
Waking at night short of breath, needing to sit up or open a window
A persistent cough or wheeze, sometimes with white or pink frothy phlegm
Fluid retention
Swollen ankles, feet and legs, which may pit when pressed
Rapid weight gain over a few days (more than about 2 kg in 3 days) from fluid
A swollen, bloated abdomen, loss of appetite or feeling full quickly
Needing to pass urine more often at night
General symptoms
Persistent tiredness and fatigue, and feeling that your legs are heavy
Reduced ability to exercise or carry out everyday tasks
Palpitations or a fast, irregular heartbeat
Dizziness, light-headedness or, less commonly, confusion in older people
Symptoms that need a doctor, even if mild
Heart failure can be present with few symptoms, particularly in the early stages, and breathlessness can also be caused by lung disease, anaemia, obesity or deconditioning. If you notice any of the symptoms above, particularly new swelling or breathlessness, a proper assessment is the only reliable way to tell the difference.
Causes and risk factors of heart failure
Heart failure is a syndrome rather than a single disease, and there is almost always an underlying cause or combination of causes. Finding them is a central part of the assessment, because some are treatable or even reversible.
Heart muscle and coronary disease
Coronary artery disease and previous heart attack – damage to the heart muscle or reduced blood supply
Cardiomyopathies – diseases of the heart muscle, including dilated, hypertrophic and inherited forms. Some run in families, so relatives may be offered screening
Myocarditis – inflammation of the heart muscle, often after a viral infection
Pressure, valve and rhythm problems
High blood pressure – a leading cause, particularly of heart failure with preserved ejection fraction
Heart valve disease – narrowed (stenosis) or leaking (regurgitation) valves, such as aortic stenosis or mitral regurgitation
Atrial fibrillation and other rhythm disturbances – persistently fast or irregular rhythms can weaken the heart, and heart failure can in turn trigger AF
Medical and lifestyle factors
Type 2 diabetes, obesity, chronic kidney disease and sleep apnoea
Regular heavy alcohol intake and smoking
Some cancer treatments (such as anthracyclines, certain targeted therapies and chest radiotherapy), which is why heart monitoring is often offered during and after treatment
Thyroid disease, anaemia and some infiltrative conditions such as amyloidosis
Can heart failure be prevented?
Often, yes, or at least delayed. Controlling blood pressure, diabetes and cholesterol, not smoking, keeping alcohol low, staying active, maintaining a healthy weight and treating valve disease or rhythm problems early all lower the risk. This is the principle behind “stage A” in the new classification: identifying people at risk and acting before the heart is damaged.
Triggers of sudden worsening
People with established heart failure can deteriorate suddenly because of a chest infection, a new rhythm problem, uncontrolled blood pressure, missed medication, anti-inflammatory painkillers, excessive salt or fluid intake, or a new heart problem. Recognising a trigger early often allows treatment before hospital admission becomes necessary.
When to see a doctor about heart failure
Because heart failure is common and treatable, it is better to be assessed early than to wait. Do not put new breathlessness or ankle swelling down to age without having it checked.
Arrange a prompt assessment if you have:
New or worsening breathlessness, reduced walking distance or unusual tiredness
Swollen ankles or legs, or weight gain of more than about 2 kg over 3 days
Needing more pillows to sleep, or waking breathless at night
A persistent cough, particularly at night or on lying down
Palpitations, dizziness or light-headedness
Known heart failure with a change in symptoms, or side effects from your medication
A history of heart attack, high blood pressure, valve disease, cardiomyopathy or cancer treatment with new symptoms
Call 999 immediately if you have:
- Severe breathlessness at rest or unable to speak in full sentences
- Chest pain or pressure, especially with sweating or breathlessness
- Fainting or collapse
- Coughing up pink or frothy phlegm
- Sudden confusion, blue lips or severe weakness
How heart failure is diagnosed
The aim of assessment is to confirm that heart failure is present, to decide which type it is, and to find the cause. This usually starts with a consultation and examination, followed by a small number of tests.
1. History and examination
Your cardiologist will ask about symptoms, exercise tolerance, previous heart problems, medicines, alcohol and family history, and will check pulse, blood pressure, heart sounds, lungs and fluid retention. This can begin as a telephone or video consultation, with examination and tests arranged in person where needed.
2. ECG
An electrocardiogram (ECG) looks for rhythm problems such as atrial fibrillation, evidence of a previous heart attack and signs of heart strain.
3. Blood tests
A natriuretic peptide blood test (BNP or NT-proBNP) is a hormone released by a strained heart. A low level makes heart failure less likely, while a raised level supports the diagnosis and prompts an echocardiogram. Other tests include kidney function, electrolytes, blood count, iron studies, thyroid function, glucose or HbA1c and cholesterol, which help to identify causes and guide treatment.
4. Echocardiogram
An echocardiogram is the key test. It measures the ejection fraction (which determines your heart failure type), shows the size and thickness of the heart chambers, checks the valves and estimates pressures. Without it, heart failure cannot be classified correctly.
5. Tests to find the cause
Depending on the findings, further tests may include heart rhythm monitoring, stress echo or exercise testing, CT coronary angiography or invasive coronary angiography to look for coronary disease, and cardiac MRI to assess the heart muscle for scarring, inflammation or inherited and infiltrative conditions. Genetic testing may be considered in suspected inherited cardiomyopathy.
Heart failure treatment options
Treatment aims to relieve symptoms, keep you out of hospital, slow or reverse damage to the heart and improve survival. The 2026 ESC guideline emphasises starting foundational medical therapy promptly, then adding further therapies and optimising doses, supported by structured follow-up, rather than leaving treatment unchanged. The right plan depends on your heart failure type and cause.
Heart failure with reduced ejection fraction (HFrEF)
Four groups of medicine form the foundation, and each improves survival and reduces hospital admissions: an ARNI (sacubitril/valsartan) or ACE inhibitor / ARB, a beta-blocker, a mineralocorticoid receptor antagonist (MRA) such as spironolactone or eplerenone, and an SGLT2 inhibitor (dapagliflozin or empagliflozin).
Water tablets (diuretics) are used as needed to control fluid and breathlessness. They relieve symptoms but are not a substitute for the foundational medicines.
Medicines are usually started at low doses and increased gradually, with blood tests to check kidney function and potassium.
Further options include intravenous iron for iron deficiency and other medicines for those who remain symptomatic.
Heart failure with preserved ejection fraction (HFpEF)
An SGLT2 inhibitor reduces hospital admissions and is recommended for most people with HFpEF.
The 2026 guideline gives MRA therapy, so it is now part of the approach across the spectrum.
Diuretics relieve congestion, and blood pressure, atrial fibrillation, diabetes and obesity are treated actively as drivers of the condition.
In people with HFpEF (ejection fraction 50% or more) and obesity (BMI 30 or more), the guideline recommends considering weight-loss medicines such as semaglutide or tirzepatide to improve symptoms.
Devices and procedures
An implantable defibrillator (ICD) may be recommended in selected people with a weak heart despite at least three months of optimal medicines, to prevent sudden cardiac death.
Cardiac resynchronisation therapy (CRT) is a special pacemaker that coordinates the heart’s contraction in selected people, particularly with a wide QRS on the ECG.
Treating the cause matters: revascularisation for coronary disease, valve repair or replacement, catheter ablation or cardioversion for atrial fibrillation.
In advanced heart failure (stage D), specialist options include mechanical heart support and transplantation, and palliative care input alongside active treatment.
Cardiac rehabilitation and self-care
Exercise-based cardiac rehabilitation improves symptoms, fitness and quality of life and reduces admissions. Ask to be referred.
Vaccinations (influenza, COVID-19, pneumococcal and RSV where offered) reduce the risk of infections that can trigger a decline.
Review medicines regularly. Avoid anti-inflammatory painkillers such as ibuprofen, and check with a pharmacist before taking any new over-the-counter medicine or supplement.
Living with heart failure
Heart failure is a long-term condition, and the things you do every day make a real difference to how you feel.
Day-to-day self-care
Take your medicines every day as prescribed, and do not stop them if you feel well. They are protecting your heart.
Weigh yourself every morning after passing urine and before breakfast. A gain of more than about 2 kg in 3 days suggests fluid build-up, so contact your heart failure team or GP promptly.
Stay active. Regular walking and other moderate activity are safe and beneficial for most people. Build up gradually and ask about cardiac rehabilitation.
Salt: avoid adding salt and limit processed foods. Fluid restriction is only needed for some people, so follow the advice you are given.
Alcohol and smoking: keep alcohol low (and avoid it completely if alcohol contributed to your heart failure) and stop smoking.
Keep vaccinations up to date and report infections early.
Sleep, mood and wellbeing: low mood and anxiety are common and treatable. Support is available from the British Heart Foundation, the NHS and Pumping Marvellous.
Driving and travel: many people can continue to drive. DVLA rules depend on your symptoms and licence type, so discuss it with your cardiologist.
Regular reviews: your doses, kidney function and potassium should be checked regularly, with the aim of reaching the best tolerated doses of each medicine.
Heart failure prognosis and outlook
Heart failure is usually progressive if untreated, but modern treatment can improve symptoms, slow progression, reduce hospital admissions and extend life for many people.
In HFrEF, taking all four foundational medicines can substantially reduce the risk of dying or being admitted to hospital, and in some people the heart’s pumping function partially or fully recovers (for example after treating a rhythm problem, valve disease or myocarditis). Medicines should generally be continued even if the heart improves.
Outlook depends on the underlying cause, your age and other health conditions, kidney function and how early treatment starts and how well it is tolerated.
Hospital admissions and worsening symptoms are signs that treatment needs reviewing, and are an opportunity to optimise therapy rather than a sign that nothing more can be done.
In advanced heart failure, specialist treatments and palliative care support can improve quality of life. Your cardiologist can discuss your individual outlook honestly with you.
Heart failure key facts
Heart failure means the heart cannot pump or fill as well as it should. It does not mean the heart has stopped.
Heart failure becomes more common with age.
The 2026 ESC guideline classifies heart failure into two phenotypes: reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF). The middle “mildly reduced” group has been removed.
The guideline also describes stages A to D, from at risk of heart failure to advanced heart failure.
Typical symptoms are breathlessness, tiredness and swollen ankles, but early heart failure may cause few symptoms.
Diagnosis relies on an ECG, a natriuretic peptide blood test and an echocardiogram, with further tests to find the cause.
In HFrEF, four foundational medicines (ARNI or ACE inhibitor, beta-blocker, MRA and SGLT2 inhibitor) improve survival and reduce hospital admissions.
In HFpEF, SGLT2 inhibitors and MRAs are recommended, along with treating blood pressure, rhythm problems, diabetes and obesity.
Weight-loss medicines (semaglutide, tirzepatide) may be considered in HFpEF with obesity.
Daily weights, exercise, vaccination and regular review help keep you well and out of hospital.
Heart failure is sometimes called congestive heart failure, a term used when fluid builds up in the lungs or legs. It is the same condition: “congestive” describes one way it can show itself, not a separate disease.
Guidelines and sources
This page follows current UK and European guidance:
NICE NG106: Chronic heart failure in adults: diagnosis and management.
McDonagh TA et al. 2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure. European Heart Journal 2021;42:3599-3726.
McDonagh TA et al. 2023 Focused Update of the 2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure. European Heart Journal 2023;44:3627-3639.
DVLA: Cardiovascular disorders: assessing fitness to drive (GOV.UK).
Heart failure questions and answers
These are the questions patients most often ask about heart failure.
What is heart failure?
Heart failure is a long-term condition in which the heart cannot pump blood around the body effectively, or cannot fill properly, so organs do not receive enough blood and fluid builds up in the lungs and legs. It does not mean the heart has stopped working.
Does heart failure mean my heart is about to stop?
No. Heart failure is not the same as a heart attack or a cardiac arrest. It means the heart is working less efficiently. With treatment, many people remain stable for many years.
What are the symptoms of heart failure?
The most common are breathlessness, tiredness and swollen ankles. Others include needing extra pillows to sleep, a persistent cough, weight gain from fluid, and reduced ability to exercise.
What causes heart failure?
The commonest causes are coronary artery disease and heart attack, high blood pressure, heart valve disease, cardiomyopathy and atrial fibrillation. Diabetes, obesity, kidney disease, alcohol and some cancer treatments also contribute. Finding the cause is an important part of the assessment.
How is heart failure diagnosed?
Diagnosis combines an assessment of your symptoms with an ECG, a natriuretic peptide (BNP or NT-proBNP) blood test and an echocardiogram. Further tests, such as heart rhythm monitoring, cardiac MRI or coronary angiography, look for the cause.
What is the difference between HFrEF and HFpEF?
In HFrEF the heart muscle is weak and pumps less blood with each beat. In HFpEF the heart pumps normally but is stiff and does not relax and fill properly. The type is determined by the ejection fraction on an echocardiogram and influences which treatments are used.
Can heart failure be cured or reversed?
Heart failure is usually a long-term condition, but some causes can be treated, for example a fast heart rhythm, a faulty valve, alcohol or inflammation of the heart muscle, and the heart can sometimes recover. Even then, medicines are usually continued to prevent it recurring.
What medicines are used to treat heart failure?
It depends on the type. In HFrEF the foundation is an ARNI or ACE inhibitor, a beta-blocker, an MRA and an SGLT2 inhibitor, plus diuretics for fluid. In HFpEF, SGLT2 inhibitors, MRAs and diuretics are used alongside treatment of blood pressure, rhythm, diabetes and obesity.
Can I exercise if I have heart failure?
Yes, for most people regular moderate exercise is safe and beneficial, and cardiac rehabilitation is recommended. Build up gradually, and seek advice if you get chest pain, severe breathlessness, dizziness or sudden weight gain.
How much salt and fluid should I have?
Avoid adding salt and limit processed foods. Strict fluid restriction is only needed for some people, such as those with severe heart failure or low blood sodium, so follow your own team’s advice rather than a general rule.
What is the life expectancy with heart failure?
This varies widely and depends on the cause, age, other conditions and how well treatment is tolerated. With modern medicines, outcomes have improved considerably, and many people live for many years. Your cardiologist can give you a more personal estimate.
Is heart failure hereditary?
Heart failure itself is not inherited, but some causes such as certain cardiomyopathies run in families. If a cause with a genetic component is suspected, your cardiologist may arrange family screening or genetic testing.
Can I have a heart failure assessment privately?
Yes. A consultation by telephone, video or face to face in Peterborough or Corby can review your symptoms, with an ECG and echocardiogram arranged as needed. Investigations such as ECG reporting and cardiac monitoring are available across the UK.
Questions to ask your cardiologist about heart failure
Questions to ask your cardiologist
Bring this list to your appointment. It can help you get the most from your time with your cardiologist or heart failure nurse. Write down the answers so you can share them with your family.
Which type of heart failure do I have (reduced or preserved ejection fraction), and what stage?
What has caused it, and have the cause and its treatment been fully investigated?
Am I on all the recommended foundational medicines at the best tolerated doses?
What side effects should I look out for, and what should I do if I get them?
Do I need an ICD or CRT device, or further tests such as a cardiac MRI or angiogram?
Could weight, blood pressure, diabetes, kidney function or sleep apnoea be treated better?
What weight gain or symptoms should prompt me to call, and who do I call?
How much exercise is safe, and can I be referred to cardiac rehabilitation?
Should my relatives be screened?
How often should I be reviewed, and which tests will be repeated?
Heart failure diagrams and visual aids
Heart failure: the heart cannot pump blood as well as the body needs, causing breathlessness, tiredness and swelling.
Image: myUpchar, Depiction of a person suffering from heart failure, Wikimedia Commons. Licensed under CC BY-SA 4.0.
What heart failure means
Illustration of a healthy heart compared with a heart in heart failure.
In heart failure the heart cannot pump, or cannot fill, as well as it should. Blood and fluid can then back up into the lungs and legs, which causes breathlessness, swollen ankles and tiredness. It does not mean the heart has stopped.
Two types of heart failure
The two types of heart failure: reduced ejection fraction (weak pump) and preserved ejection fraction (stiff heart).
Your cardiologist works out which type you have from an echocardiogram, which measures how strongly the heart squeezes (the ejection fraction). Both types can feel the same, but treatment is different, so knowing your type matters.
The four stages of heart failure
The four stages of heart failure, from at risk (A) to advanced (D).
The stages describe how far heart failure has progressed, from being at risk (stage A) to advanced heart failure (stage D). Recognising the earlier stages matters, because treatment can prevent progression.
Your daily heart failure check
A simple daily check: when to carry on, when to call your team or GP, and when to call 999.
A simple guide to your day-to-day checks, when to contact your heart failure team or GP, and when to call 999. Weigh yourself every morning, and ask your team for a personal plan.
If you have breathlessness, ankle swelling or a diagnosis of heart failure, you may benefit from a telephone consultation or video consultation to review your symptoms and treatment, or a face-to-face consultation in Peterborough or Corby for a more comprehensive assessment.
Investigations such as echocardiography, ECG reporting, cardiac monitoring and exercise stress echo may be recommended to establish the type and cause of heart failure.
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Medically reviewed by Dr Salam Salloum, Consultant Cardiologist. Last reviewed: . This page is for general information and does not replace personal medical advice.