Enlarged Heart (Cardiomegaly)

Medically Reviewed by James Beckerman, MD, FACC on August 20, 2022
4 min read

An enlarged heart may have several causes. including high blood pressure and coronary artery disease.

It 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.

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, though, the heart's pumping ability declines.

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

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

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

The most common cause of a weakened heart is blockages that affect the heart's blood supply (coronary artery disease) and high blood pressure. There can be other causes, including:

Frequently, no cause is known. Your doctor may refer to this as idiopathic dilated cardiomyopathy.

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 flat)
  • Leg swelling
  • Weight gain, particularly in your midsection
  • Tired feeling
  • Palpitations or skipped heartbeats

Some folks may never have symptoms. Others may have little things 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 you have that could be tied to congestive heart failure. Other times, it’s found out through a test for something else.

An ultrasound of your heart -- you may hear it called an echocardiogram -- is the best way to diagnose it. There’s no pain or risk from it. 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 things can help discover an enlarged heart, such as:

Your history: Shortness of breath or other symptoms of congestive heart failure may provide clues.

A physical exam: You may have swelling. An enlarged heart can also produce abnormal sounds when a doctor listens with a stethoscope.

Chest X-ray: Dilated cardiomyopathy increases the heart’s size on a chest X-ray film.

Cardiac catheterization: This 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 enlarged heart, such as:

CT scans and MRIs: These may help diagnose an enlarged heart in certain situations.

Biopsy: Very rarely, a doctor may obtain a small tissue sample from inside the heart to determine the cause of an enlarged heart.

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: Stopping use of the harmful substance can improve the symptoms of an enlarged heart and improve heart function.

Heart valve disease: Surgery or a less invasive procedure can sometimes repair or replace a damaged heart valve that is causing cardiomegaly.

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. This means the heart doesn’t have to pump as much. These also help ease leg swelling.

Angiotensin-converting enzyme (ACE) inhibitors and beta-blockers. Most often, these treat high blood pressure, but they also improve heart health.

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.

In very few people with cardiomegaly and severe congestive heart failure, a heart transplant may be recommended.