What is heart failure? (Part 3/3)
- Faraz Afzal
- Nov 4
- 5 min read
Heart Failure with Reduced Pump Function (HFrEF)
When people hear the word “heart failure,” this is often the type they imagine – when the heart’s pump has become too weak to deliver enough blood to the body. In medical terms, this is called heart failure with reduced ejection fraction (HFrEF). A related condition is HFmrEF, or heart failure with moderately reduced ejection fraction. For most patients, the distinction between these two is less important – the principles of diagnosis and treatment are largely the same.
This article is based on European (ESC)guidelines for heart failure but is written for readers without a medical background.
1. What does “reduced pump function” mean?
The heart is a muscular pump. With every beat, the left ventricle fills with blood and pushes it out to the body. The percentage of blood pumped out with each contraction is called the ejection fraction (EF). A normal EF is typically above 50–55%. In heart failure with reduced pump function, EF is below 40%, and in “moderately reduced” function it often lies between 40–50%. The lower the EF, the more severe the failure. EF is usually measured by ultrasound of the heart (echocardiography).
2. How common is it?
Among all patients with heart failure, the “pump-weak” types (HFrEF and HFmrEF) account for about half of all cases. In large European registries, 50–60% of patients had reduced ejection fraction, and another 15–20% were in the moderate range (HFmrEF). The rest have heart failure with preserved pump function (HFpEF), discussed in part 2 of this series.
This means that reduced-pump heart failure is very common, and it is the type for which modern medicine has made the most progress in treatment over the past 20–30 years.
3. Why does the pump weaken?
In adults in Europe, the three most common causes are:
1. Narrowed coronary arteries or previous heart attack – The heart muscle has been weakened because part of it has become scar tissue after a heart attack.
2. Heart valve disease – A leaky or narrowed valve makes the heart work harder over time, eventually leading to failure.
3. Long-standing rhythm disorders – The heart beats too fast or irregularly for long periods, working itself to exhaustion.
There are also less common causes: inherited heart muscle diseases, long-term alcohol use, inflammation of the heart, or side effects after cancer therapy. Identifying the underlying cause is essential, because the treatment often depends on it. In addition to medication, the doctor may use ultrasound, ECG, and blood tests – and sometimes MRI of the heart – to determine the cause.
The key message: if the underlying cause can be treated, it should be. It is difficult to restore heart function if, for example, a severe valve-leak remains untreated.
4. How does it feel?
The symptoms are the same as described in part 1 of this series:
Shortness of breath, first on exertion – later possibly at rest
Reduced exercise tolerance
Swelling of ankles or legs
Nighttime coughing or the need for extra pillows
Weight gain due to fluid retention
None of these symptoms alone proves heart failure, but when they match findings from heart tests, the diagnosis becomes likely.
5. How is the diagnosis made?
The doctor combines several assessments:
Medical history and physical examination
ECG: a completely normal ECG makes heart failure less likely, although a normal ECG does not rule heart failure,
Blood test for natriuretic peptides (BNP or NT-proBNP): low values argue against heart failure
Echocardiography: the key examination
Sometimes X-ray, MRI, or other tests
If ultrasound shows EF below 50% and the patient has typical symptoms, the diagnosis of heart failure with reduced pump function is made.
6. Treatment – the essentials
The goal of treatment is always threefold: longer life, fewer hospital admissions, and a better quality of life.
a) The four main pillars
According to current guidelines, patients with HFrEF should, if tolerated, receive four classes of heart failure medications:
ACE inhibitor / ARNI / ARB – helps the heart recover over time
Beta-blocker – slows the heart rate, improves efficiency, and reduces rhythm disturbances
MRA (spironolactone or eplerenone) – has mild diuretic effects and supports heart recovery
SGLT2 inhibitor (dapagliflozin or empagliflozin) – originally for diabetes, but now proven to reduce death and hospitalization in heart failure, even in non-diabetic patients
Together these drugs form guideline-directed medical therapy (GDMT) and have the strongest evidence for improving survival.
b) Diuretics
If you retain fluid and feel swollen or short of breath, you will also receive a diuretic. It may not directly strengthen the heart, but it relieves symptoms and improves daily life. The goal is to find the lowest effective dose.
c) Treat the cause
Narrowed arteries: may require angioplasty or bypass surgery
Valve disease: may need repair or replacement
Rapid heart rhythm: must be controlled
Without addressing the underlying cause, if identified, the heart will not stabilize.
d) Advanced therapies
Some patients have such reduced pump function that they are at risk of dangerous heart rhythms. They may be offered an implantable cardioverter-defibrillator (ICD) to prevent sudden cardiac arrest. Others with electrical delay between the heart’s chambers may benefit from a cardiac resynchronization pacemaker (CRT), which helps the heart beat in a more coordinated way. These options are evaluated by specialists using strict criteria.
7. Prognosis – serious but improving
Heart failure with reduced pump function is a serious condition. In older studies, about 4 in 10 patients died within five years. That sounds dramatic – and it is – but outcomes have improved with earlier diagnosis and modern therapy. Many patients experience improvement in ejection fraction when properly treated and the underlying cause is corrected.
Even if the heart improves, medication should not be stopped, as the disease can recur. Hospitalization for heart failure is a warning sign and worsens prognosis – keeping the patient stable at home with adequate medical treatment is a major goal.
8. What can you do yourself?
Take your medication every day – even when you feel well
Monitor your weight (contact your doctor or HF nurse if it increases by more than 2–3 kg in a few days)
Stay moderately active – daily walks are beneficial
Limit salt and excessive fluids if advised by your doctor
Do not smoke
Keep up with recommended vaccines, such as flu and COVID-19
9. When to seek help
Contact your doctor or heart failure team if you experience:
Sudden worsening of breathlessness
Rapidly increasing swelling
Dizziness or fainting
Persistent palpitations
Weight gain over a few days
These may indicate an exacerbation that requires early treatment
.
In summary: Heart failure with reduced pump function means the heart has become a weaker pump – often due to previous heart disease. Today, we have highly effective medications and therapies that can slow progression, improve quality of life, and, in many cases, restore heart function. Early diagnosis, addressing the underlying cause, and careful self-management make the greatest difference.
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