An enlarged heart can be due to a condition you’re born with or one that develops over time. Treatments address the underlying cause and may include medications, surgery, or lifestyle changes.

An enlarged heart (cardiomegaly) means that your heart is bigger than normal. Your heart can become enlarged if the muscle works so hard that it thickens, or if the chambers dilate.

An enlarged heart isn’t a disease. It’s a symptom of a heart defect or condition that makes the heart work harder, such as:

An enlarged heart can’t pump blood as efficiently as a heart that’s not enlarged. This can lead to complications like stroke and heart failure.

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Enlarged heart compared to a healthy heart. Cristie Wilson.

Research tells us that having an enlarged heart is often a sign that you have a serious heart condition that needs treatment. Without treatment for the underlying cause, your health and even your life may be at risk.

Since many people with an enlarged heart do not have any symptoms, it’s possible they won’t know that anything is wrong. In fact, some people don’t learn they have an enlarged heart until a doctor orders imaging tests to get a closer look at their heart.

Regardless of whether you know you have an enlarged heart, it does affect your body.

When you have an enlarged heart, it means that your heart — or part of your heart — has gotten thicker or stretched out. That makes it harder for your heart to pump blood efficiently throughout your body.

As a result, you may eventually find it harder to function normally. You may experience fatigue and shortness of breath, or other effects.

You may also develop edema (swelling) because your heart’s inefficient pumping allows blood to flow backward and collect in the arms or legs, or even the abdomen or face.

There can be other effects on your body, too. When you have cardiomegaly, you’re more susceptible to developing blood clots in the lining of your heart.

If a blood clot breaks off and makes its way to your bloodstream, it could cause you to have a stroke. You may also develop an irregular heart rhythm.

Sometimes an enlarged heart doesn’t cause any symptoms. When symptoms do occur, they can include:

  • shortness of breath
  • an irregular heart rhythm (arrhythmia) or heart palpitations
  • swelling in the legs and ankles caused by fluid buildup (edema)
  • fatigue
  • dizziness

Symptoms that indicate a medical emergency include:

  • chest pain
  • trouble catching your breath
  • pain in your arms, back, neck, or jaw
  • fainting

Your heart can enlarge because of a condition you’re born with — called a congenital condition — or a heart problem that develops over time.

Any disease that makes your heart work harder to pump blood through your body can cause an enlarged heart. Just as the muscles of your arms and legs get bigger when you work them, your heart gets bigger when it works harder. Increased pressures in the heart can also cause chamber dilation.

The most common causes of an enlarged heart are ischemic heart disease and high blood pressure.

Ischemic heart disease occurs when narrowed arteries, caused by fatty deposits that build up in your arteries, prevent blood from getting to your heart.

Other conditions that can make your heart enlarge include:


Cardiomyopathy is a progressive heart disease with several types. Diseases that damage the heart muscle can cause it to enlarge. The more damage that occurs, the weaker and less able to pump the heart becomes.

Heart valve disease

Infections, connective tissue diseases, and some medications can damage the valves that keep blood flowing in the right direction through your heart. When blood flows backward, the heart has to work harder to push it out.

Heart attack

During a heart attack, blood flow to part of the heart is blocked completely. The lack of oxygen-rich blood damages the heart muscle.

Thyroid disease

The thyroid gland produces hormones that regulate the body’s metabolism. Both overproduction (hyperthyroidism) and underproduction (hypothyroidism) of these hormones can affect the heart rate, blood pressure, and size of the heart.

Irregular heart rhythm (arrhythmia)

If you have an irregular heart rhythm, instead of beating in its familiar pattern, the heart flutters or beats too slowly or too quickly. An irregular heart rhythm can cause blood to back up in the heart and eventually damage the muscle.

Congenital conditions

Congenital cardiomegaly is a heart disorder you’re born with. Congenital heart defects that cause this symptom include:

Other causes

Other possible causes of an enlarged heart include:

You’re more likely to get cardiomegaly if you’re at risk of heart diseases. The following conditions can increase your risk:

  • high blood pressure
  • obesity
  • sedentary lifestyle
  • parent or sibling with an enlarged heart
  • past heart attack
  • metabolic disorders, like thyroid disease
  • heavy drug or alcohol use
  • valvular heart disease

Your doctor will start with a physical exam and discuss your symptoms with you.

A number of different tests can check the structure and function of your heart. A chest X-ray may be the first test your doctor orders because it can show whether your heart is enlarged.

Tests like the following can help your doctor find the cause of the enlargement:

  • Echocardiogram (echo) uses sound waves to look for problems with your heart’s chambers.
  • Electrocardiogram (EKG or ECG) monitors the electrical activity in your heart. It can diagnose an irregular heart rhythm and ischemia.
  • Blood tests check for substances in your blood produced by conditions that cause an enlarged heart, like thyroid disease.
  • A stress test involves walking on a treadmill or pedaling a stationary bike while your heart rhythm and breathing are monitored. It can show how hard your heart is working during exercise.
  • CT scans use X-rays to produce detailed images of your heart and other structures in your chest. It can help diagnose valve disease or inflammation.
  • MRI scans use strong magnets and radio waves to produce pictures of your heart.

In pregnancy

During pregnancy, doctors can use a test called a fetal echocardiogram to diagnose heart defects in the unborn baby. This test uses sound waves to create pictures of the baby’s heart.

Your doctor might recommend a fetal echocardiogram if you have a family history of cardiomegaly or heart defects, or if your baby has a genetic disorder like Down syndrome.

Your doctor will prescribe a treatment plan for the condition that’s causing your enlarged heart. For example:

Other procedures can fix congenital heart defects. If you try a few treatments and they don’t work, you may need a heart transplant.

Lifestyle changes

You can manage an enlarged heart with lifestyle changes like these:

  • Exercise. Exercise on most days of the week. Ask your doctor which types of exercises are safest for you.
  • If you smoke, quit. Methods like nicotine replacement products and therapy can help you stop. Quitting is often difficult, but a doctor can help build a plan that works for you.
  • Mange your weight. If you have overweight or obesity, work with your doctor to create a sustainable weight loss plan.
  • Limit certain foods. Limit salt, cholesterol, and saturated and trans fats in your diet. Read more about the best diet for heart health.
  • Avoid certain substances. Limit your intake of alcohol and caffeine. Avoid illegal drugs entirely.
  • Relax. Practice relaxation techniques like meditation or yoga to reduce stress.

The conditions that cause cardiomegaly can damage the heart muscle. They can lead to complications if left untreated, such as:

  • Heart failure. When the left ventricle enlarges, it can lead to heart failure. Then the heart isn’t able to pump enough blood to the body.
  • Blood clots. When the heart doesn’t pump as well as it should, blood can pool and clump together into clots. A blood clot can travel to the brain and get stuck in a blood vessel there, causing a stroke.
  • Heart murmur. When valves in your heart don’t close properly, they create an abnormal sound called a murmur.
  • Cardiac arrest. If your heart is enlarged, it may not get enough blood. That can lead to cardiac arrest. The heart can stop working properly, which can cause sudden death.

You may not be able to prevent conditions that occur before birth. But you can prevent later damage to your heart that can make it enlarge by:

Also see a doctor for regular checkups to make sure your heart is healthy. If you have a heart problem, you might also need to see a cardiologist.

Your outlook depends on the underlying cause of your enlarged heart. Following the treatment plan your doctor recommends can help keep your heart healthy and prevent any complications.