Heart failure with reduced ejection fraction is a condition where the heart’s main pumping chamber cannot squeeze forcefully enough to deliver adequate blood throughout the body. While the heart continues to beat, it struggles to meet the body’s needs, leading to fluid buildup and a range of symptoms that can significantly impact daily life. Understanding this condition and the available approaches to managing it can help patients work with their healthcare teams toward better outcomes.

Understanding Heart Failure with Reduced Ejection Fraction

Heart failure with reduced ejection fraction, often abbreviated as HFrEF, represents a specific type of heart failure where the lower left chamber of the heart, known as the left ventricle, loses its ability to pump blood effectively. This condition is sometimes called systolic heart failure because the problem occurs during systole, which is the phase when the heart contracts to push blood out to the rest of the body.^[1]

To understand how well the heart is pumping, doctors measure something called the ejection fraction. This number tells us what percentage of blood inside the left ventricle gets pushed out with each heartbeat. Think of the heart as a water balloon that squeezes but never completely empties. A healthy heart pumps out more than 55 percent of the blood in the left ventricle with each squeeze. When someone has HFrEF, their ejection fraction drops to 40 percent or less, meaning the heart is leaving more blood behind with each beat instead of pushing it forward to nourish the body’s organs and tissues.^[1][5]

There is also a category called heart failure with mid-range ejection fraction, where the ejection fraction falls between 41 and 49 percent. Some patients who receive proper treatment may see their ejection fraction improve over time, which is then called heart failure with improved ejection fraction.^[1]

When the heart cannot pump blood forward effectively, the blood backs up into the blood vessels. First, it accumulates in the vessels of the lungs, and then it backs up into the large veins in the abdomen and legs. This backup causes the blood vessels to become engorged, or congested, and fluid begins to leak out of them. When fluid leaks into the lungs, it causes shortness of breath. When it leaks into soft tissues of the abdomen and legs, it causes swelling. This is why the condition is often referred to as congestive heart failure.^[20]

Epidemiology: How Common Is This Condition

Heart failure with reduced ejection fraction is a widespread health problem affecting millions of people. In the United States alone, more than six million individuals aged 20 years or older are living with heart failure, and this number is expected to climb to 8.5 million Americans by the year 2030.^[3][7] The condition represents a major and growing public health challenge, partly because the population is aging, but also because improvements in treatments for other heart diseases have helped people survive longer, sometimes resulting in changes to the heart that eventually lead to heart failure.^[5]

Among older adults, heart failure becomes increasingly common with age. Approximately 14 percent of men and 13 percent of women over the age of 80 have heart failure. More than 60 percent of older adults living with heart failure also have at least five other long-term health conditions, and more than half experience some level of disability.^[6] Heart failure is the leading cause of hospitalization for people aged 65 and older, and it is one of the most frequent reasons for death and hospital admissions in industrialized nations.^[7][10]

The statistics around hospitalizations paint a concerning picture. About 20 percent of people who are hospitalized for heart failure must return to the hospital again within 30 days because they do not feel better or their condition worsens. Up to 50 percent return within six months for the same problem.^[6] Despite these sobering numbers, there is hope. The introduction of new medications and the rigorous implementation of evidence-based treatment recommendations have led to reductions in recent years in both mortality rates and the frequency of hospitalizations for patients with HFrEF.^[10]

Causes of Heart Failure with Reduced Ejection Fraction

Many different problems can damage or weaken the heart muscle enough to cause heart failure with reduced ejection fraction. Understanding the underlying causes is important because treating these root problems can sometimes prevent the condition from worsening.^[1]

Coronary artery disease and heart attacks are among the most common causes. The coronary arteries are the blood vessels that supply the heart muscle itself with oxygen-rich blood. When these arteries become narrowed or blocked, blood flow to parts of the heart muscle is limited or cut off entirely. Without adequate blood flow, the heart muscle becomes weakened or damaged, and its ability to pump blood is impaired. A heart attack, which occurs when blood flow to part of the heart is suddenly blocked, can cause permanent damage to the heart muscle.^[1][7]

High blood pressure, also called hypertension, places extra strain on the heart over time. When blood pressure is elevated, the heart must work harder to pump blood against the increased pressure in the arteries. This extra work can eventually weaken the heart muscle, making it less effective at pumping.^[1][7]

Cardiomyopathy refers to disease of the heart muscle itself. In this condition, the heart muscle becomes weakened for various reasons, including genetic factors or viral infections, and cannot pump blood properly. Viral myocarditis, which is a viral infection of the heart muscle, causes inflammation that affects the heart’s pumping ability.^[1]

Diabetes is another significant contributor. This condition results in persistently high blood sugar levels, which over time can lead to problems with the heart muscle and blood vessels. Arrhythmias, or irregular heart rhythms, reduce the pumping effectiveness of the heart because the electrical signals that coordinate the heartbeat are disrupted.^[1][7]

Problems with heart valves can also lead to HFrEF. Aortic stenosis occurs when the opening of the aortic valve, which controls blood flow out of the heart to the rest of the body, becomes narrowed. The heart must work harder to push blood through this narrowed opening, and over time this extra effort weakens the muscle. Mitral regurgitation happens when the mitral valve, which controls blood flow between two chambers on the left side of the heart, does not close properly. This allows blood to leak backward, increasing the volume of blood the heart must handle and stretching and weakening the heart muscle over time.^[1]

Risk Factors for Developing HFrEF

Certain factors increase a person’s likelihood of developing heart failure with reduced ejection fraction. Age is one of the most significant risk factors, with the condition becoming much more common in people over the age of 65.^[7]

Lifestyle choices play an important role. Using tobacco products, cocaine, or consuming excessive amounts of alcohol all increase risk. Having an inactive or sedentary lifestyle, where a person does not engage in regular physical activity, also contributes to higher risk. Eating a diet high in salt and fat can lead to conditions like high blood pressure and high cholesterol, which in turn damage the heart over time.^[7]

Pre-existing medical conditions significantly raise the risk of developing HFrEF. These include high blood pressure, coronary artery disease, diabetes, kidney disease, and a body mass index higher than 30, which indicates obesity. People who have already had a heart attack face elevated risk because of the damage done to the heart muscle during the event.^[7]

Family history matters as well. Having close relatives who have experienced congestive heart failure increases a person’s own risk, suggesting that genetic factors may play a role in some cases. Certain medications, particularly some cancer drugs used in chemotherapy, can also damage the heart muscle and increase the risk of heart failure.^[7]

Symptoms: What People Experience

The symptoms of heart failure with reduced ejection fraction can vary from person to person and may range from mild to severe. Sometimes symptoms come and go, and occasionally people may have mild symptoms or none at all for a period of time. However, this does not mean the heart failure has disappeared. Unfortunately, the condition usually worsens over time, and as it does, symptoms may become more numerous or more severe.^[7]

Shortness of breath is one of the most common and bothersome symptoms. People may feel breathless during physical activity, such as walking up stairs or carrying groceries. As the condition progresses, shortness of breath can occur even when lying down or resting. Some people wake up at night gasping for air, a frightening experience that forces them to sit up or stand to breathe more easily.^[2][7]

Fatigue and weakness are also hallmark symptoms. People with HFrEF often feel tired and worn out, even after activities that previously seemed easy. This fatigue can limit their ability to exercise or perform daily tasks, affecting their quality of life and independence.^[2][7]

Fluid retention leads to visible swelling, typically in the ankles, legs, and feet. This swelling, called edema, occurs because fluid is leaking out of congested blood vessels into the surrounding tissues. Some people also experience swelling in the abdomen, which may make the stomach feel full, bloated, or hard. Weight gain can occur rapidly when the body retains excess fluid.^[2][7]

Other symptoms include a rapid or irregular heartbeat, which people may notice as heart palpitations, or a sensation that the heart is racing, fluttering, or skipping beats. A persistent dry, hacking cough can develop, particularly at night, and some people experience wheezing. Loss of appetite or feelings of nausea may occur, and some people need to urinate more frequently at night.^[2][7]

Poor blood flow may cause changes in skin color. Depending on a person’s natural skin tone, the skin may appear blue or gray, though these color changes may be harder or easier to see in different individuals.^[2]

Prevention Strategies

While not all cases of heart failure with reduced ejection fraction can be prevented, many lifestyle changes and medical interventions can reduce the risk or delay the onset of the condition. Prevention focuses on addressing the risk factors and underlying conditions that damage the heart.^[7]

Maintaining a healthy diet is fundamental. A balanced diet should include plenty of fruits and vegetables, with a goal of at least five portions daily. Meals should be based on starchy foods like potatoes, bread, rice, or pasta, and should include some dairy or dairy alternatives. Protein sources such as beans, pulses, fish, eggs, and meat should be included, while foods high in saturated fat, salt, and sugar should be limited. For people already at risk or diagnosed with heart problems, limiting salt intake is particularly important because salt causes the body to retain fluid, which puts extra strain on the heart.^[17][19]

Regular physical activity helps keep the heart strong and improves overall cardiovascular health. Exercise does not have to be strenuous to be beneficial. Even moderate activities like walking can make a difference when done regularly. For people who already have heart problems, a structured cardiac rehabilitation program that includes exercise tailored to their abilities can be very helpful.^[17][19]

Stopping smoking is one of the most important steps anyone can take to protect their heart. Smoking damages blood vessels and heart muscle, and quitting reduces the risk of many heart problems. People who need help quitting can speak with their healthcare provider about support services and medications that can make the process easier.^[17][19]

Limiting alcohol consumption is also advisable. While people with heart failure can usually continue to drink alcohol in moderation, it is best not to exceed 14 alcohol units per week. For some individuals whose heart failure is directly related to alcohol use, stopping entirely may be necessary.^[17][19]

Managing existing medical conditions is crucial for prevention. This includes controlling high blood pressure, managing diabetes effectively, treating high cholesterol, and addressing coronary artery disease. Taking medications as prescribed and attending regular medical appointments helps keep these conditions under control and reduces the risk of heart damage.^[7]

Getting vaccinated can also help protect heart health. Everyone with heart failure should receive the annual flu vaccine and the one-time pneumococcal vaccination, as these infections can put significant strain on an already weakened heart. These vaccinations are typically available at doctor’s offices or local pharmacies.^[17]

Pathophysiology: What Happens in the Body

To understand heart failure with reduced ejection fraction, it helps to know what happens inside the body when the heart cannot pump effectively. The heart is a muscular pump divided into four chambers. The two upper chambers, called atria, receive blood returning to the heart. The two lower chambers, called ventricles, pump blood out to the body and lungs. In HFrEF, the problem centers on the left ventricle, which is responsible for pumping oxygen-rich blood to the entire body.^[1]

In a healthy heart, when the left ventricle contracts during systole, it squeezes forcefully enough to push more than 55 percent of the blood it contains out into the aorta, the body’s main artery. From there, the blood travels through a network of arteries to deliver oxygen and nutrients to every organ and tissue. In HFrEF, the left ventricle’s muscle is weakened or damaged, so it cannot squeeze as forcefully. As a result, only 40 percent or less of the blood is ejected with each heartbeat. The remaining blood stays in the ventricle, which means less blood reaches the body’s organs and tissues.^[1][5]

This reduced forward flow creates a backup effect. Blood that should have been pumped forward begins to accumulate in the heart and the blood vessels leading to it. This congestion first affects the lungs. The blood vessels in the lungs become engorged with backed-up blood, and fluid leaks from these vessels into the tiny air sacs where oxygen exchange normally occurs. This is called pulmonary congestion, and it makes breathing difficult because the lungs cannot expand and contract normally.^[2][20]

As the backup worsens, it extends to the veins throughout the body, particularly in the abdomen and legs. These veins also become engorged, and fluid leaks into the surrounding soft tissues, causing the visible swelling that many people with HFrEF experience. The kidneys, which depend on adequate blood flow to function properly, may not receive enough blood, leading to fluid retention that further worsens swelling.^[2]

Because organs and tissues are not receiving adequate oxygen-rich blood, people feel fatigued and weak. The brain may not get enough oxygen, leading to confusion or difficulty concentrating in severe cases. The body tries to compensate for the reduced blood flow by making the heart beat faster and by narrowing blood vessels to maintain blood pressure, but these compensatory mechanisms can eventually make the problem worse by placing additional strain on the already weakened heart.^[5]

Over time, if left untreated, the heart’s pumping ability continues to decline. The left ventricle may stretch and enlarge in an attempt to hold more blood, but this stretching further weakens the muscle. In some cases, the backup of blood can also affect the right side of the heart, which pumps blood to the lungs. When both sides of the heart are involved, symptoms become more severe and widespread.^[2][7]