By Kevin James Cyr 

 Medically reviewed by Anisha Shah, MD

Mild cardiomegaly is when your heart is just a little bigger than it should be (slightly larger than your fist). You may not have symptoms of a slightly enlarged heart. Its size might only be noticed when you have an imaging test of your chest, like an X-ray.1

Mild cardiomegaly can be caused by high blood pressure, heart valve diseases, blood disorders, drug or alcohol use, and inherited conditions. Sometimes, it's just a temporary problem. For example, the heart may enlarge during pregnancy but typically goes back to normal size after the person gives birth.

While having mild cardiomegaly is less serious than more significant cases of heart enlargement, it's not something you should ignore. If the underlying condition causing it is not treated, mild cardiomegaly can get worse and increase your risk for heart disease or stroke.

This article discusses mild cardiomegaly. It explains the different causes of an enlarged heart, common treatments, how it's diagnosed, and what you can do to prevent it.

Ariel Skelley / Verywell

What Are the Symptoms of Mild Cardiomegaly?

Many people with mild cardiomegaly never have symptoms. But in some people, cardiomegaly may cause:23

• Fatigue and dizziness

• Heart palpitations

• Shortness of breath

• Wheezing

• Coughing, especially when sleeping

• Weight gain

• Inability to lie on the stomach due to chest discomfort

• Edema (swelling) of the abdomen, legs, and feet

Heart Disorders

Mild cardiomegaly is generally not considered a disease of the heart; instead, it's a consequence of certain heart diseases. Identifying the cause of mild cardiomegaly will make management and treatment more effective. 

Several heart disorders can lead to mild cardiomegaly:

• High blood pressure: High blood pressure (hypertension) is the most frequent cause of an enlarged heart. High blood pressure makes it harder for your heart to pump blood to the rest of your body. To understand this connection, it will help to think of your heart as a muscle. Just like your biceps can get bigger to help you lift heavy weights, your heart can get bigger to generate more force. However, that increased pressure makes your heart work harder to deliver blood.

• Diseases of the heart valves: Aortic valve disease and mitral valve disease are also causes of an enlarged heart.4 When the valves of the heart are defective, blood flow within the heart is disrupted and the heart will get bigger to accommodate the extra blood.

How It's Treated

If you have high blood pressure, medications are often used to keep your heart from working so hard. The medications try to keep your blood pressure within a safe range for your heart to work.

Treatments for heart valve disease include procedures to repair or replace the valves which can help control the size of the heart.

Blood Disorders

Certain blood disorders can cause mild cardiomegaly, including:

• Anemia

• Beta thalassemia

• Sickle cell disease

Blood disorders affect the delivery of oxygen to tissues in the body by hemoglobin. For example, in anemia, the body has a reduced hemoglobin level. This leads to decreased oxygen delivery in the body. The heart will try to compensate for anemia by increasing in size to push blood more rapidly through the body. 

How It's Treated

Treatments for blood disorders that affect the heart vary. For example, with anemia, you might be prescribed iron supplements to support your body’s production of red blood cells. With conditions like beta-thalassemia or sickle cell disease, you may need to have blood transfusions.

Pregnancy

Pregnancy can change the size of the heart temporarily. In pregnancy, your heart is responsible for pumping not just your blood but the blood to the fetus as well. The extra demand makes the heart work harder and get bigger.

How It's Treated

Usually, cardiomegaly in pregnancy is reversible; the heart goes back to a normal size a few months after a woman gives birth.

Drugs and Alcohol

Using cocaine, methamphetamine, or large amounts of alcohol is known to cause a heart disease called cardiomyopathy.4 Stimulants such as cocaine and methamphetamine put the heart under a lot of stress. Over time, the stress causes the heart to get bigger. Alcohol can also create toxins in the body that damage the heart.

How It's Treated

Ultimately, these substances can cause the heart to enlarge as it tries to work harder. In many cases, the heart will return to normal if the use of these substances is limited or stopped.

How is Mild Cardiomegaly Diagnosed?

After performing a physical exam and possibly an X-ray, your healthcare provider may order one or more of the following tests:5

• Electrocardiogram (ECG), in which small electrical conductors (electrodes) are temporarily attached to your chest to measure the electrical activity of your heart.

• Ambulatory ECG, for which you will wear a small portable machine on your waist with electrodes connected to your chest. The device will measure your heart's electrical activity over the course of one or two days.

• Echocardiogram, in which sound waves are used to make a picture of the heart, similar to an ultrasound

• Stress test, in which electrodes are attached to the chest while you walk or jog on a treadmill to test for abnormal heart rhythms

• Cardiac catheterization, in which a thin, flexible tube is threaded through a blood vessel to your heart. Dye may be fed through the blood vessel to check the heart's pumping function. Or, a biopsy of the heart muscle can be taken this way.

• CT or MRI, for which you will lie beneath a giant scanner that generates detailed images of your heart

Who Is Most Likely to Get Cardiomegaly?

Your risk of developing cardiomegaly may be higher if you have a family history of cardiomegaly, a heart defect, past or present heart disease, or hypertension (high blood pressure).6

How is Mild Cardiomegaly Prevented?

You can’t always prevent cardiomegaly. For example, if you are more likely to develop the condition because of your genes, that’s not a risk factor you can change. Some people are also born with an enlarged heart (congenital).

However, there are some other risk factors that you do have some control over. Many of the steps that you can take to support your heart health overall may also help prevent cardiomegaly, or prevent complications if you already have an enlarged heart.

What you eat and how much you move are two key aspects of your lifestyle that affect your heart health positively or negatively. If you're at risk for an enlarged heart or have one and you are trying to keep it from getting worse, making some changes to your diet and exercise routine can be helpful.

• Diet: Like other heart-healthy diets, a diet for mild cardiomegaly will be balanced and nutritious. The best diet for an enlarged heart is one that contains plenty of fruits, vegetables, fiber-rich whole grains, a moderate amount of healthy fats, and limited processed foods with added sugar. Stay hydrated with water and consider cutting back (or cutting out) caffeine.

• Exercise: If you have an enlarged heart, getting regular physical activity and avoiding too much sedentary time can help improve your cardiovascular (and overall) health. However, talk to your provider about the type and amount of exercise that is safe for you.7

• Weight: Diet and exercise are key for weight management—another important step to take to keep your heart healthy. If you are at risk for mild cardiomegaly or have an enlarged heart, talk to your provider about what your weight goal should be and how you can get to and maintain it.

Other ways you can lower your risk for cardiomegaly and possibly keep it from getting worse include:8

• Substance use: Do not use substances that can harm your heart, which includes limiting alcohol and quitting smoking.

• Prioritizing sleep: Create a supportive sleep environment in your bedroom, practice sleep hygiene, and address any sleep trouble with your provider.

• Managing stress: Find things that bring you joy and help you unwind and make time for them.

• Taking care of your overall health: Stay up to date with recommended health screenings, get vaccines you're eligible for, treat and manage any, other health conditions you have (like high blood pressure or diabetes), and take steps to avoid infectious illnesses like washing your hands.

• Following your healthcare provider’s treatment plan: Have regular check-ups and follow-up appointments, take your medications as prescribed, and let your provider know about any changes in your health or questions you have.

Summary

Mild cardiomegaly means that the heart is a little bigger than normal. It is a sign that something is going on with the heart—for example, it's being affected by a condition like high blood pressure. In some cases, a person is born with an enlarged heart. There are also some temporary causes, like being pregnant.

It's important to find out what is causing your heart to be larger than normal to ensure you get the right treatment. While you can't always prevent an enlarged heart, living a heart-healthy lifestyle can help lower your risk and avoid complications.

8 Sources

American Heart Association. What is cardiomyopathy in adults?.

Bumrungrad International Hospital. Cardiomegaly.

MedPark Hospital. What is cardiomegaly?.

American Heart Association. Dilated cardiomyopathy (DCM).

Mercy. Cardiomegaly.

St. Clair Health. Enlarged heart.

Keck Medicine of USC. What causes an enlarged heart?.

Heart and Stroke Foundation of Canada. Enlarged heart.

By Kevin James Cyr
Kevin is a physician-in-training at Stanford University School of Medicine with a focus in cardiovascular disease and bioengineering. His publications have earned international awards, and his work has been featured in major media outlets such as NBC News.