Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at May 25, 2016

Cardiomegaly or enlarged heart is a condition in which the heart is larger than normal and cannot pump as effectively. If not treated promptly and correctly, this condition can have serious health consequences.


Definition & Facts

Cardiomegaly is an enlarged heart that has begun to lose function. There are two main conditions associated with cardiomegaly: dilated cardiomyopathy and hypertrophic cardiomyopathy. In cardiomegaly caused by dilation, the heart is enlarged due to consistent high blood pressure combined with a restriction of blood flow. This stretches out muscle fibers so they cannot pump as effectively.

Hypertrophic cardiomyopathy is usually inherited and leads to cardiomegaly through overdevelopment of the heart muscle, which makes it thick and ineffective. In both cases, the size of the heart can interfere with its ability to move blood throughout the body and keep tissues well-oxygenated. 

Symptoms & Complaints

Cardiomegaly is usually asymptomatic in its early phases. As it progresses, most symptoms are related to heart failure. People will often experience chest pain, heart palpitations, and other common cardiac symptoms as the cardiac muscle must work harder to contract.

In addition, there are often signs that the body is not moving fluid adequately, including swelling in legs and arms, abdominal swelling from fluid build-up, and weight gain. People often feel that they are swollen and carrying too much fluid in general.

As the heart becomes less able to pump effectively, individuals may have signs of low oxygenation such as fainting, fatigue, and shortness of breath. The shortness of breath is often worse at night, because fluid builds up in the lungs when people lay down. Patients with an enlarged heart often notice that many symptoms are worse when they are physically active or under stress, both of which require the heart to pump harder. People who notice these symptoms should see a doctor promptly.


Genetic factors are a major cause of cardiomegaly. People who have a family member with an enlarged heart should tell their doctor so they can be monitored for the disorder. In addition, different forms of cardiovascular disease can cause it, including hypertension, coronary artery disease, heart failure, heart valve disease, and a history of angina or heart attack

There are also lifestyle factors that can cause cardiomegaly or make it worse. Obese people and those with diabetes are more likely to have enlarged hearts. It has also been linked to the use of certain substances including tobacco, alcohol, and cocaine.

Conditions that increase fluid in the body can make the heart work harder and contribute to an enlarged heart as well. These conditions include kidney disease, pulmonary hypertension, and liver disease.

Diagnosis & Tests

If a medical care provider suspects a person has cardiomegaly, they will do several tests. These include:

  • Chest X-ray to determine the size of the heart and also see if the lungs and surrounding blood vessels have been affected.
  • Electrocardiogram to determine how well the heart's electrical wiring is functioning.
  • Echocardiogram to look for anatomical changes and examine how much blood the heart is pumping.
  • Exercise stress test to examine whether the heart can adequately handle increased oxygen demands.

These tests are not painful and not invasive. In some cases, the physician may also order one or more optional tests to get more information about an enlarged heart, such as:

  • Cardiac CT scan or MRI to see the heart's structure in three dimensional detail.
  • Blood tests to check for underlying disorders as well as signs of heart attack.
  • Cardiac biopsy to examine the structure of cells.

These tests will not only help the doctor to diagnose cardiomegaly, but also to look for possible causes of it. They also will rule out other diseases.

Treatment & Therapy

There are many treatments available for people who are diagnosed with cardiomegaly. First, the physician will treat any underlying causes that may have contributed to the development. For example, if the enlarged heart is caused by a valve disorder, the doctor may recommend surgery to fix the valve.

If a person has hypertension, he or she will be put on blood pressure medication. Medications that lower blood pressure include diuretics, ACE inhibitors, and angiotensin II receptor antagonists. These have the additional benefit of reducing the swelling and edema that cardiomegaly can cause. In addition, people may be prescribed beta blockers or digoxin, both of which improve the heart's function and make it more efficient at pumping. 

If there is concern about blood clots forming, patients will be given anticoagulants to prevent a stroke. If the cardiomegaly has caused an arrhythmia, antiarrhythmic drugs may be prescribed or the use of a pacemaker may be recommended.

Doctors also may prescribe medications to help reduce the side effects of an enlarged heart. For example, they may prescribe a medication via inhaler if a person suffers from shortness of breath.

Prevention & Prophylaxis

While cardiomegaly can often be successfully treated, it cannot be reversed. Because damage to the heart muscle will last a lifetime, prevention is crucial.

People should tell their doctor if there is a history of cardiomegaly or other heart disease in their family. Because hypertension and other cardiovascular diseases can cause an enlarged heart, it is important to take medications for these disorders as prescribed.

In addition, living a healthy lifestyle, with adequate exercise, and healthy diet, can help prevent cardiomegaly. Lastly, preventing cardiomegaly may involve avoiding excessive use of alcohol and any use of tobacco, cocaine, and other recreational drugs.