What Causes Low Ejection Fraction And How To Improve It?

Ejection fraction is a simple measurement with a big job. It tells your doctor how well your heart’s main pumping chamber, the left ventricle, is working. The number represents the percentage of blood that leaves the heart with each beat. A normal heart pumps out about 55 to 70 percent of its blood. When that number drops below 50 percent, it is considered low. A low ejection fraction means your heart muscle has weakened and cannot push enough blood to meet your body’s needs. Understanding what causes this drop and what you can do about it is the first step toward protecting your heart.

What Is Ejection Fraction and Why Does It Matter?

Think of the left ventricle as a water balloon. When it squeezes, it should push out most of the water inside. Ejection fraction measures that squeeze. It is calculated by dividing the amount of blood pumped out by the total amount of blood in the ventricle before the beat.

This number matters because it reflects the heart’s pumping strength. When ejection fraction falls, blood flow to organs and tissues slows down. You may feel tired, short of breath, or notice swelling in your legs and ankles. These are signs that your heart is working harder than it should.

Doctors measure ejection fraction using an echocardiogram, which is an ultrasound of the heart. Other tests like an MRI or a nuclear heart scan can also measure it. The test is painless and takes about 30 to 60 minutes. Your doctor will likely repeat the test over time to track changes in your heart function.

A normal ejection fraction is 55 to 70 percent. A measurement between 41 and 49 percent is considered mildly reduced. Anything at or below 40 percent is classified as reduced ejection fraction, which is the medical definition of heart failure with reduced ejection fraction.

What Causes Low Ejection Fraction?

Low ejection fraction happens when the heart muscle becomes damaged or weakened. The most common cause is coronary artery disease. When the arteries that supply blood to the heart narrow or become blocked, the heart muscle does not get enough oxygen. Over time, this starves the muscle and weakens it.

A heart attack is a direct cause of low ejection fraction. During a heart attack, a blocked artery cuts off blood flow to part of the heart muscle. That section of muscle dies and is replaced by scar tissue, which cannot contract. The more muscle that dies, the lower the ejection fraction becomes.

Cardiomyopathy is another major cause. This is a disease of the heart muscle itself. It can be inherited or acquired. Dilated cardiomyopathy, the most common type, causes the left ventricle to stretch and enlarge. The stretched muscle cannot squeeze effectively, so ejection fraction drops.

Other causes include:

• High blood pressure that goes untreated for years
• Heart valve problems, especially aortic stenosis or mitral regurgitation
• Viral infections that inflame the heart muscle
• Alcohol abuse over many years
• Certain chemotherapy drugs, particularly anthracyclines
• Thyroid disorders, both overactive and underactive

Sometimes the cause is unclear. This is called idiopathic cardiomyopathy. In these cases, the heart weakens without a known trigger. Your doctor will run tests to rule out the common causes before settling on this diagnosis.

Can Low Ejection Fraction Be Reversed?

In some cases, yes. The heart has a remarkable ability to recover if the cause is treated quickly and effectively. This is called reverse remodeling. When the underlying stress on the heart is removed, the muscle can sometimes regain strength.

For example, if a blocked artery caused the problem, opening it with a stent or bypass surgery can restore blood flow. If alcohol damaged the heart, stopping drinking can lead to significant improvement. If a valve problem is the culprit, repairing or replacing the valve may allow the heart to recover.

Medications can also help the heart heal. Several classes of drugs have been shown to improve ejection fraction over time. These include beta-blockers, ACE inhibitors, ARBs, and a newer group called SGLT2 inhibitors. These medications reduce the workload on the heart and block harmful hormones that make heart failure worse.

Recovery is not guaranteed. The extent of improvement depends on how much muscle damage occurred and how quickly treatment began. Some people see their ejection fraction return to normal. Others see partial improvement. Some see no change. Your doctor can give you a realistic picture based on your specific situation.

It is important to understand that a low ejection fraction does not automatically mean your heart cannot improve. Many people with heart failure live active, full lives with proper treatment. The heart is not a static organ. It responds to the conditions around it.

What Lifestyle Changes Help Improve Ejection Fraction?

Lifestyle changes support medical treatment but do not replace it. If your doctor prescribes medication, take it as directed. Lifestyle changes work alongside medication to give your heart the best chance of recovery.

Regular exercise is one of the most effective lifestyle changes. Cardiac rehabilitation programs are specifically designed for people with heart failure. These programs combine supervised exercise with education about heart-healthy living. Studies consistently show that regular aerobic exercise improves symptoms and quality of life in people with reduced ejection fraction.

Start slowly. Walking for 10 to 15 minutes a day is a reasonable starting point for most people. Your doctor or a cardiac rehab team can help you create a plan that matches your current fitness level. The goal is to build up to 30 minutes of moderate activity most days of the week.

Diet matters too. A heart-healthy diet emphasizes vegetables, fruits, whole grains, lean protein, and healthy fats. Limiting sodium is especially important for people with heart failure. Too much salt makes your body hold onto fluid, which forces your heart to work harder. Most guidelines recommend keeping sodium under 2,000 milligrams per day, but your doctor may suggest a different target.

Weigh yourself daily. Sudden weight gain of two to three pounds in a day or five pounds in a week can mean fluid is building up. This is an early warning sign that your heart failure may be getting worse. Call your doctor if you see this pattern.

What Medications Are Used to Treat Low Ejection Fraction?

Medication is the backbone of treatment for low ejection fraction. The goal is to reduce the heart’s workload, block harmful stress hormones, and protect the heart muscle from further damage.

Beta-blockers slow the heart rate and lower blood pressure. This gives the heart more time to fill and reduces the oxygen demand of the muscle. Carvedilol, metoprolol succinate, and bisoprolol are the beta-blockers most commonly used for heart failure.

ACE inhibitors and ARBs relax blood vessels. This lowers blood pressure and makes it easier for the heart to pump blood forward. They also block a hormone called angiotensin that can damage the heart over time.

Mineralocorticoid receptor antagonists, like spironolactone and eplerenone, block another harmful hormone called aldosterone. These medications reduce fluid retention and prevent scar tissue from forming in the heart.

SGLT2 inhibitors were originally developed for diabetes but have shown significant benefits in heart failure. Dapagliflozin and empagliflozin reduce the risk of hospitalization and death in people with reduced ejection fraction, even in those without diabetes.

Diuretics, commonly called water pills, do not improve ejection fraction directly. They relieve symptoms by removing excess fluid. Furosemide and bumetanide are common examples. These medications help with shortness of breath and swelling but do not change the underlying heart function.

When Is a Device or Surgery Needed?

Some people need more than medication. If ejection fraction remains low despite optimal medical therapy, your doctor may discuss device options. These devices are not for everyone, but they can be life-changing for the right candidates.

An implantable cardioverter-defibrillator, or ICD, is a small device placed under the skin that monitors your heart rhythm. If a dangerous arrhythmia occurs, the ICD delivers a shock to restore normal rhythm. This device does not improve ejection fraction. It prevents sudden cardiac death, which is a real risk in people with low ejection fraction.

A cardiac resynchronization therapy device, or CRT, helps the heart beat in a coordinated way. In some people with heart failure, the left and right sides of the heart beat out of sync. This wastes energy and reduces pumping efficiency. A CRT device sends small electrical signals to both sides of the heart to coordinate their contractions.

Surgery may be an option for specific causes. Coronary bypass surgery can restore blood flow to heart muscle that is still alive but underperforming. Valve repair or replacement can fix structural problems that strain the heart. In severe cases where no other treatment works, a left ventricular assist device or heart transplant may be considered.

What Is the Outlook for Someone With Low Ejection Fraction?

The outlook varies widely from person to person. It depends on the cause, how much damage occurred, how quickly treatment started, and how well you respond to medication. Some people improve significantly. Others stabilize at a lower ejection fraction but live well for many years with treatment.

What matters most is consistent care. People who take their medications, attend follow-up appointments, and make lifestyle changes tend to do better than those who do not. Heart failure is a chronic condition that requires ongoing management, not a one-time fix.

Your ejection fraction number is one piece of the picture. It does not define your entire prognosis. Some people with low ejection fraction feel fine and are highly active. Others with normal ejection fraction struggle with symptoms. Your doctor looks at your symptoms, exercise capacity, blood tests, and other factors to understand your overall health.