Enlarged Heart (Cardiomegaly)

Medically Reviewed by Zilpah Sheikh, MD on January 02, 2024
Written by Matthew Hoffman, MD
9 min read

An enlarged heart means you have a condition that has increased the size of your heart.

All or some of your heart may become enlarged. Often, especially in its early stages, you may feel no symptoms from an enlarged heart.

Your heart may not pump blood effectively, which can cause congestive heart failure. It may improve over time. But most people with an enlarged heart need lifelong treatment with medications.

Is having an enlarged heart serious?

It can be. It depends on the underlying cause. A disease that makes your heart work harder can enlarge your heart, as can a diseased heart muscle or coronary artery disease.

The heart enlarges because of damage to the heart muscle. Up to a point, an enlarged heart can still pump blood normally. As the condition progresses, the heart's pumping ability declines.

Dilated cardiomyopathy is the main type of enlarged heart. The walls of both sides of the heart (also known as ventricles) become thin and stretched. This enlarges your heart.

In the other types of enlarged heart, the muscular left ventricle becomes very thick. High blood pressure can cause your left ventricle to enlarge (a type known as hypertrophy). This thickening, which doctors call hypertrophic cardiomyopathy, can be inherited.

An enlarged heart keeps more of its pumping ability when it's “thick” rather than “thin.”

Sometimes, damage to the heart, or related conditions, can cause an enlarged heart. Other times, there is no known reason why the heart enlarges and gets weak. Your doctor may refer to this as idiopathic dilated cardiomyopathy. The most common causes of a weakened heart are blockages that affect the heart's blood supply (coronary artery disease), heart attack, and high blood pressure. There can be other causes, including:

  • Viral infection. Viruses that affect the heart can cause myocarditis, which refers to heart muscle inflammation. Myocarditis can weaken your heart muscle and cause an enlarged heart.
  • Abnormal heart valve. The heart's four valves assist in blood flow. Damage to one or more of them can interrupt your blood flow and enlarge the heart's chambers.
  • Fluid buildup around the heart. Pericardial effusion refers to the collection of fluid in the sac around your heart. An enlarged heart from this condition can be detected via a chest X-ray.
  • Cardiac amyloidosis. This rare condition causes amyloid protein to build up in the blood and collect in the body's organs, including the heart, leading to a thickening of the heart's walls.
  • Pregnancy. Your heart may enlarge around the time of delivery (peripartum cardiomyopathy).
  • Chronic kidney disease. A poorly functioning heart affects the kidneys. Chronic kidney disease helps speed up cardiovascular aging due to conditions that cause an enlarged heart.
  • Anemia. The body needs a constant supply of oxygen-rich blood to its organs and tissues. Anemia causes red blood cells to carry less oxygen and makes the heart pump harder to deliver needed oxygen levels.
  • Excessive iron. Too much iron in your heart can lead to swelling in its lower left chamber.
  • Thyroid issues. An underactive or overactive thyroid gland can trigger heart problems that lead to an enlarged heart.
  • Alcohol or cocaine abuse. Long-term heavy drinking and cocaine use can create an enlarged heart.
  • Pulmonary hypertension. High blood pressure in your lungs makes the heart work harder to pump blood into them, causing enlargement on your heart's right side.
  • Genetic and inherited conditions. You may have been born with a congenital defect that alters your heart's function and structures, enlarging and weakening your heart.

You may have an enlarged heart due to a layer of fat around your heart that your doctor can see on an X-ray. Frequent and sustained aerobic exercise may also enlarge your heart. Unless there are other heart conditions present, neither of these reasons is cause for concern.

Sometimes, an enlarged heart causes no symptoms. If it becomes unable to pump blood well enough, you may get symptoms of congestive heart failure, such as:

  • Shortness of breath (especially when active or when lying down)
  • Leg swelling
  • Weight gain, particularly in your midsection
  • Feeling tired
  • Palpitations or skipped heartbeats

Some folks may never have symptoms. Others may show subtle signs that don’t change for years. Still, others may have shortness of breath that steadily gets a little worse.

An enlarged heart may be discovered after you and your doctor talk about symptoms and your medical history. You may have swelling. An enlarged heart can also produce abnormal sounds when a doctor listens with a stethoscope. Shortness of breath or other symptoms of congestive heart failure may also provide clues. Other times, an enlarged heart can be diagnosed during tests for other health issues.

An ultrasound of your heart, also called an echocardiogram, is the best way to diagnose it. An echocardiogram doesn't involve any pain or risk. It measures the heart's:

  • Size
  • Muscle thickness
  • Pumping function

In some cases, it can help your doctor figure out what’s causing your enlarged heart.

Other tests and procedures can help discover an enlarged heart, such as:

  • Chest X-ray. It helps doctors examine the condition of the heart and lungs. If your heart appears enlarged on an X-ray, your doctor will probably order additional tests to make sure your heart is enlarged and find out potential causes.
  • Cardiac catheterization. This test looks for blockages in the coronary arteries. The heart's size and pumping function can also be checked.
  • Blood tests. These may be done to check for things that can lead to an enlarged heart or for substances in the blood that result from damage to your heart.
  • CT scans and MRIs. These collect images of your heart.
  • Exercise and stress tests. Your doctor will have you walk on a treadmill or use a stationary bike to see how physical activity affects your heart. If you can't exercise, your doctor may give you a medicine that simulates how exercise affects your heart.
  • Biopsy. Very rarely, a doctor may obtain a small tissue sample from inside your heart to determine the cause of an enlarged heart.

If you're pregnant, you might undergo a fetal echocardiogram if:

  • You have a family history of genetic heart disease.
  • You have taken certain prescription or recreational drugs that affect the heart of your developing fetus.
  • You are diabetic, have lupus, or certain other medical conditions.
  • You used in vitro fertilization to conceive.
  • You had an infection such as German measles (rubella).
  • A genetic abnormality is found in your developing fetus or doctors have heard an irregular heartbeat.

Your risk of developing an enlarged heart increases if you:

  • Have/had a family member with the condition
  • Had a prior heart attack or have a family history of them
  • Smoke, drink too much alcohol, or have a substance abuse disorder
  • Don't exercise 
  • Have hypertension (high blood pressure)

Often, these focus on the underlying cause, such as:

  • Coronary artery disease: Opening the blockages in the blood vessels that supply oxygen to the heart can improve blood flow to the heart muscle. If your heart is enlarged because of a blockage, its pumping may improve.
  • Hypertension: Controlling high blood pressure can prevent further damage. It can also make your heart work better.
  • Alcohol or drug use: Avoiding harmful substances can improve heart function as well as the symptoms of an enlarged heart. 
  • Heart valve disease: Surgery or a less invasive procedure can sometimes repair or replace a damaged heart valve that is causing cardiomegaly.

Enlarged heart medications

When an enlarged heart is causing congestive heart failure, other treatments focus on easing symptoms and keeping your heart working as it is, such as:

  • Diuretics. “Water pills” make you pee more and help get rid of excess sodium. This means the heart doesn’t have to pump as much. These also help ease leg swelling.
  • Blood pressure meds. Drugs that treat high blood pressure, such as angiotensin-converting enzyme (ACE) inhibitors and beta-blockers, also improve heart health.
  • Anticoagulants. These blood-thinning drugs lower the risk of blood clots, which can contribute to stroke or heart attack.
  • Anti-arrhythmia drugs. These medicines treat slow or irregular heartbeats.

Surgery and other medical treatments

  • Implantable cardioverter-defibrillator. A device put into the chest can restart the heart if it stops beating. Some of these can also help the heart pump more effectively.
  • Pacemaker. This implanted device stimulates a slow or irregularly beating heart.
  • Heart valve surgery. If one or more of your heart valves is faulty, then surgical repair may be necessary.
  • Left ventricular assist device (LVAD). If you have heart failure, this mechanical implant helps your heart pump while you await a heart transplant. It can also be used as an alternative treatment.
  • Coronary bypass. This surgery restores blood flow by creating a path around blocked arteries.
  • Heart transplant. In very few people with cardiomegaly and severe congestive heart failure, a heart transplant may be recommended.

Lifestyle changes to treat your enlarged heart include:

  • A heart-healthy diet
  • Maintaining a healthy weight
  • Exercise, as appropriate
  • Managing your intake of fluids
  • Controlling high blood pressure, cholesterol, and diabetes, if you have them

Diet for enlarged heart treatment

Watch your portion sizes and eat nutrient-rich, low-calorie foods while limiting foods rich in calories and sodium, as well as fast foods.

Foods to include:

  • Whole grains
  • Fresh and frozen fruits and vegetables
  • Nuts and seeds
  • Olive and canola oils
  • Low-fat dairy products and proteins

Foods to limit or avoid:

  • Salt
  • Trans and saturated fats
  • Fried foods
  • Breads and desserts made with refined flour
  • Processed, fatty, and organ meats
  • Alcohol and caffeine

Depending on the cause of your enlarged heart, you may have complications including:

  • Heart murmur. An enlarged heart can keep your heart valves from closing properly and allow blood to flow backward. A heart murmur is the sound this process makes. These are usually not harmful and will be monitored by your doctor.
  • Blood clots. Clots that form inside your heart or elsewhere and travel to your lungs or brain may cause a pulmonary embolism or stroke.
  • Heart failure. An enlarged left ventricle (left lower chamber) limits the capacity of your heart to pump blood, leading to heart failure.
  • Cardiac arrest. Too fast, too slow, or irregular heartbeats can cause multiple problems including fainting, cardiac arrest, or sudden death.

Be aware of your family health history. Let your doctor know if any family member has had a diagnosis of an enlarged heart or any conditions that lead to it. Treating underlying conditions early can help prevent an enlarged heart or keep your condition stable.

What you can do:

  • Exercise and eat a heart-healthy diet.
  • Keep a check on your blood pressure, cholesterol levels, or diabetes (if you have it).
  • Continue taking your prescription medicines.
  • Don't smoke, or stop if you do.
  • Avoid recreational drugs.
  • Drink moderate amounts of alcohol.
  • Aim for 8 hours of sleep every night.

Treatment for certain underlying conditions may help an enlarged heart return to normal size. Or your cardiomegaly may be chronic. Whatever the cause, cardiomegaly is a manageable but potentially serious condition that you may have to monitor or treat for the rest of your life.

Contact your doctor immediately if you experience:

  • Chest pain
  • Pain or tingling in your neck, jaw, back, or arms
  • Breathlessness
  • Fainting

You are at greater risk for an enlarged heart if you have a family history of cardiomegaly, heart attacks, or untreated high blood pressure. An enlarged heart puts you at greater risk for conditions such as heart failure or stroke. Depending on the underlying cause, medical management of your enlarged heart may include medications, implantable devices, or surgery.

How long can someone live with an enlarged heart?

Life expectancy for those with cardiomegaly is not easily measured and depends on the seriousness of your symptoms as well as your age and underlying conditions. Left untreated, an enlarged heart can cause multiple chronic conditions including heart failure.

How do you treat an enlarged heart?

Doctors first treat the underlying cause of your enlarged heart. You can help in your treatment by adopting a heart-healthy lifestyle, including no smoking or heavy drinking; managing your weight, blood pressure, and cholesterol; regular exercise; and treating underlying conditions such as thyroid disease, sleep apnea, anemia, and irregular heart rhythms.

Can an enlarged heart go back to normal?

Temporary stresses to your heart such as pregnancy can create an enlarged heart that returns to normal size after delivery. Conditioned athletes also can have larger hearts.

Can an enlarged heart be left untreated?

Left untreated, an enlarged heart can lead to passing out, irregular heart rhythms, heart attack, or death.