Heart Failure: What Ejection Fraction Means and How It Is Treated

Your echocardiogram report says "ejection fraction 35%", or "EF preserved". The words "heart failure" can be frightening. They do not mean your heart has stopped. They mean your heart is not pumping or filling as well as your body needs. This guide explains ejection fraction and how treatment depends on it.

What heart failure is

Heart failure is a condition where the heart cannot pump enough blood to meet the body's needs, or can only do so with higher pressures inside the heart [4]. Fluid can back up into the lungs, legs, and belly.

Common symptoms include [4]:

• Shortness of breath, especially with activity or when lying flat
• Swelling in the feet, ankles, legs, or belly
• Tiredness and weakness
• Sudden weight gain from fluid
• A cough or wheeze, or waking up short of breath

Common causes include coronary artery disease, past heart attack, high blood pressure, valve disease, diabetes, and some heart muscle diseases.

What ejection fraction means

Ejection fraction (EF) is the percentage of blood that leaves the left ventricle, the main pumping chamber, with each beat. If the ventricle holds 100 mL and pumps out 55 mL, the EF is 55%. EF is usually measured by an echocardiogram (heart ultrasound). It can also be measured by MRI or other scans.

What your doctor looks at

Heart failure types by ejection fraction

A universal definition from major heart failure societies in the US, Europe, and Japan groups heart failure by EF [3]. US and Canadian guidelines use the same groups [1] [2]:

• Heart failure with reduced EF (HFrEF): EF 40% or less
• Heart failure with mildly reduced EF (HFmrEF): EF 41% to 49%
• Heart failure with preserved EF (HFpEF): EF 50% or more
• Heart failure with improved EF: EF was 40% or less before and is now above 40%

Four medicine groups for reduced EF

For HFrEF, the 2022 AHA/ACC/HFSA guideline and the 2021 Canadian Cardiovascular Society and Canadian Heart Failure Society update both recommend four medicine groups [1] [2]. Each group lowers the risk of death or hospital stays on its own.

• An ARNI (sacubitril-valsartan), or an ACE inhibitor or ARB if an ARNI cannot be used
• A beta-blocker proven in heart failure, such as bisoprolol, carvedilol, or long-acting metoprolol succinate
• A mineralocorticoid receptor antagonist (MRA), such as spironolactone or eplerenone
• An SGLT2 inhibitor, such as dapagliflozin or empagliflozin

The Canadian update stresses starting all four early and raising doses quickly, rather than one at a time over many months [2]. Diuretics, or water pills, are added as needed to clear fluid and ease symptoms [1].

Devices

If EF stays at 35% or less despite good medical treatment, some people benefit from an implantable defibrillator (ICD), which can stop a dangerous rhythm. Some also benefit from cardiac resynchronization therapy (CRT), a pacemaker that helps both sides of the heart beat together [1].

Mildly reduced and preserved EF

Evidence for HFmrEF and HFpEF is smaller but growing [1]:

• SGLT2 inhibitors reduce heart failure hospital stays in these groups too.
• Diuretics treat fluid buildup.
• Treating causes and related conditions matters a lot: high blood pressure, atrial fibrillation, diabetes, obesity, and sleep apnea.
• Some medicines used in HFrEF may help people with EF at the lower end of these ranges.

Improved EF

If your EF improves, the US guideline advises continuing your heart failure medicines [1]. In people who stopped treatment after improvement, heart function often worsened again.

Living with heart failure

• Weigh yourself each morning, after you use the toilet and before you eat. Write it down.
• Follow your team's advice on sodium and fluids.
• Take medicines every day, even when you feel well. Do not stop or change them on your own.
• Ask before you use anti-inflammatory pain pills like ibuprofen, which can worsen fluid buildup.
• Stay active as advised. Cardiac rehabilitation can help.
• Get recommended vaccines, such as flu vaccines.

Tests you may have

Ejection fraction is only one part of the picture. Your clinician may also order [1]:

• A natriuretic peptide blood test (BNP or NT-proBNP). These levels rise when the heart is under strain.
• An ECG to check the heart's rhythm and look for signs of past heart attacks.
• Blood tests for kidney function, potassium, blood count, thyroid, and blood sugar.
• A chest X-ray to look for fluid in the lungs.
• Tests to find the cause, such as an angiogram for blocked arteries.

Questions to ask your clinician

• What is my ejection fraction, and what type of heart failure do I have?
• What caused my heart failure?
• Am I on all the medicine groups recommended for my type?
• Are my doses at the target level, and if not, what is the plan?
• How much weight gain should make me call you?
• Do I need a device such as an ICD?
• When will my EF be checked again?

When to get care quickly

Call 911 or go to the emergency department for:

• Severe shortness of breath, or not being able to lie down or speak in full sentences
• Chest pain or pressure
• Fainting
• Coughing up pink, frothy mucus
• A fast or irregular heartbeat with dizziness

Call your care team the same day if you have fast weight gain, more swelling, or more shortness of breath than usual. A common rule of thumb is a gain of about 1 kg (2 to 3 pounds) in a day or 2 kg (about 5 pounds) in a week, but follow the number your team gives you.

Bottom line

Ejection fraction tells clinicians which type of heart failure you have, and that decides which medicines help most. For reduced EF, four medicine groups together lower the risk of death and hospital stays. For all types, SGLT2 inhibitors, fluid control, and daily self-care make a real difference.

Primary AI can show you the guideline and study sources behind this topic in plain language, so you can bring better questions to your appointment.