Heart failure with reduced ejection fraction, usually shortened to HFrEF, means the main pumping chamber of the heart has become weakened and squeezes out 40% or less of the blood inside it with each beat, which causes breathlessness, tiredness and swelling [1,5].
This page provides general information. It does not replace advice from a doctor or another qualified healthcare professional.
The name frightens people, and it should not. Heart failure does not mean the heart has stopped or is about to stop working [1,2]. It means the heart cannot pump blood around the body as well as it should [2]. Many people live with it for years [1].
What ejection fraction measures. The left ventricle is the heart’s main pumping chamber. It never empties completely, so doctors measure the share of blood inside it pushed out with each squeeze. A normal heart pumps out 55% to 70% [8]. Heart failure is sorted into three groups by that number [2,5]:
In HFrEF the muscle squeezes weakly, the older name being systolic heart failure. In the preserved form it squeezes normally but has stiffened and fills poorly [8]. Treatment differs, and that form has its own trialport guide.
Around 1% to 2% of adults have heart failure of all kinds, rising from about 1% of people under 55 to more than 10% of those over 70, with 3 to 5 new cases per 1,000 European adults each year. These count diagnosed people only, so the real number is likely higher. Roughly half of people hospitalized with heart failure have the reduced form [5].
In the United States around 6.7 million adults have heart failure, and about 1 in 4 people will develop it at some point. Rates are higher among Black adults, and death rates are higher in rural areas [12]. Sudden worsening is a leading reason people over 65 go into hospital [5], and heart failure remains a leading cause of illness and death worldwide [7].
HFrEF happens when the heart muscle is damaged or weakened. Finding out the cause is part of care, since it can change the treatment [5]. The common causes [1,2,5]:
Other causes include thyroid problems, low iron, kidney disease and cardiac amyloidosis, covered in our guide to ATTR-CM [1,2]. Risk rises with age, obesity and smoking [1].
The three main symptoms are breathlessness, tiredness and swelling of the ankles [5]. Breathlessness comes on with activity at first, then sometimes when lying flat or at night [1,10]. Swelling starts in the feet and can spread up the legs [2]. Many find the tiredness hardest, since ordinary jobs take much longer to recover from [10].
Symptoms are graded using the New York Heart Association classes, by how much they limit you [9]:
When to seek urgent help. In the United Kingdom, contact a doctor urgently or call NHS 111 if you become breathless lying down or during everyday activity, cough up frothy pink phlegm, or gain weight suddenly [1]. A sudden weight gain of more than 2 kg over about three days usually means fluid, and heart failure teams often ask people to report it the same day [5]. Call 999 or 911 for severe difficulty breathing, gasping or choking, lips or skin turning pale, blue or grey, or if someone passes out [1].
A family doctor takes a history, examines you and arranges tests, since symptoms alone are not accurate enough [5].
A blood test comes first. Natriuretic peptides are substances the heart releases when under strain. A result below 125 pg/mL for NT-proBNP, or below 35 pg/mL for BNP, makes heart failure unlikely [5]. In England a result above 2,000 ng/L means specialist review and a heart scan within two weeks [4].
A heart scan confirms it. An echocardiogram is an ultrasound of the heart and is the key test: it measures the ejection fraction and checks the valves [4,5,8]. An electrical tracing and a chest X-ray are usually done too, partly to look for other explanations for breathlessness [1,4]. A specialist heart failure team makes the diagnosis [4].
There is no cure, and treatment does a great deal [1,2]. The outlook has improved considerably since the first treatment trials, and that improvement has been in the reduced form [5].
Four kinds of medicine, described by what they do. These are the four pillars, and each was separately shown to help people live longer or stay out of hospital [5,13]:
Getting onto all four is the goal, and the order matters less than it used to. Rather than one fixed sequence, guidelines aim to have every person on all four, then work the doses up, and they stress getting there quickly [13]. Several ways of doing that have been suggested, including starting all four at once at low doses, though none has been tested in a trial [13]. After a hospital stay, European guidance recommends building doses up quickly before discharge and over the next six weeks [6].
Water tablets ease symptoms. Diuretics such as furosemide clear fluid and ease breathlessness and swelling, though their effect on survival has not been tested as the four pillars have [5].
Devices, surgery and advanced options. An implantable cardioverter defibrillator sits under the skin and can stop a dangerous rhythm. It is recommended where the ejection fraction is 35% or less and symptoms persist after three months of treatment [5]. Cardiac resynchronization therapy is a pacemaker that makes both sides of the heart squeeze in time, for people at the same threshold whose heart tracing shows a delay [5]. Surgery may improve blood flow or repair a valve, and where medicines and devices are not enough a heart transplant is considered, with around 90% of recipients alive at one year [1,5]. A left ventricular assist device is a pump that helps the heart while someone waits for a transplant, or where one is not possible [1,5].
Care is shared between a specialist heart failure team and the family doctor, with a review at least every six months [4]. Being in a heart failure program lowers the risk of going into hospital [5].
Weigh yourself regularly. Fluid shows on the scales before it shows anywhere else [1,2]. Many people are taught to adjust their water tablet or call the team when weight climbs by more than 2 kg in about three days [5].
Salt and fluid are individual, not a blanket rule. Guidance in England says clinicians should not routinely tell people with heart failure to restrict salt or fluid, and should advise only where intake is high or blood sodium is low [4,5].
Cardiac rehabilitation is worth asking about. Everyone diagnosed should be offered a personalized, exercise-based program [1,4]. Pooling 60 trials with 8,728 people, it cut hospital admissions by roughly a third and improved quality of life, whether run at a center, at home or online [14]. Take-up is low, so ask whether you have been referred [14].
Have the flu and pneumococcal vaccinations you are offered, and ask about iron levels and about pregnancy if relevant [1,4,5,6]. If symptoms keep worsening, ask about palliative care, which is about controlling symptoms and living better [1,4]. Predicting the course for one person is uncertain, and guidance asks clinicians to be open about that [4]. Support exists for the anxiety this brings [2].
Clinical trials test whether a treatment works and is safe. Heart failure research is busy, partly because so much has changed in the last decade. Deciding whether to look into a study is personal, and it helps to take it in steps.
Worth being clear on what a study involves:
Every trial has rules about who can take part, called eligibility criteria. For an HFrEF study they might include an ejection fraction at or below a set figure such as 40% or 35%, symptoms in a particular New York Heart Association class, a natriuretic peptide level in a set range, already taking the standard medicines at steady doses, kidney function and potassium within limits, no recent hospital stay, and not being pregnant.
trialport’s medifit helps people consider information related to possible medical suitability. It does not diagnose a condition, confirm eligibility or replace formal screening by the study team.
Explore heart failure with reduced ejection fraction clinical trials through trialport
A study can look right on paper and still be hard in practice:
trialport’s readifit helps people reflect on their understanding, motivation, time, routines, support, emotions and practical arrangements.
Useful questions to put to a research team:
Taking part is voluntary. A person can ask questions, speak with people they trust and choose not to participate.
Search for clinical trials at app.trialport.com.
Study status checked: 3 August 2026. Research moves quickly, so this list will date. For current information, search at app.trialport.com.
Coverage varies. Many countries have a general heart charity rather than a heart failure organization, and the clinic is then the best route.
Does heart failure mean my heart is about to stop?
No. It means the heart cannot pump as well as it should [1,2].
What does my ejection fraction number mean?
It is the share of blood pushed out of the main pumping chamber with each beat. 55% to 70% is normal, 41% to 49% is mildly reduced, and 40% or less is the reduced form [2,8].
Is HFrEF the same as HFpEF?
No. In HFrEF the muscle squeezes weakly. In the preserved form it squeezes normally but has stiffened and fills poorly. Treatment differs, and it has its own trialport guide [8].
Can it be cured, and can my ejection fraction go up?
There is no cure [1,2]. The number can improve with treatment, and improvement is linked to better outcomes, so ask when yours will next be measured [13].
Why four medicines when I already feel better?
Each was separately shown to help people live longer or stay out of hospital, and the benefits add up. They work on the weakness itself rather than on how you feel today, so they continue when symptoms settle [5,13].
Should I really weigh myself every day?
This is among the most useful things you can do. A gain of more than 2 kg in about three days usually means fluid rather than fat, and can be dealt with early [1,5].
Written by: trialport editorial team
Reviewed by: Keith Berelowitz, Founder and CEO, trialport
Reviewed on: 3 August 2026
Next review due: 3 August 2027
References last checked: 3 August 2026