The heart’s main pumping chamber, the left ventricle, becomes weaker, stretched, and larger in people with dilated cardiomyopathy (DCM). This makes it harder for the heart to pump blood effectively.

Dilated cardiomyopathy (DCM) is a heart condition in which the left ventricle of your heart is weak and dilated or stretched out. This causes the heart to get larger.

As a result, the heart can’t pump as it should. This triggers the release of chemicals that can cause the weakness to get worse, creating a vicious cycle.

DCM affects about 36 out of 100,000 people in the general population and accounts for about 10,000 deaths and 46,000 hospitalizations in the United States each year. It’s a major risk factor for heart failure and other complications, but better treatment options have been developed in recent years.

A timely diagnosis and proper treatment can improve the outlook for this heart condition.

Keep reading as we take a closer look at the causes and symptoms of DCM, as well as how it’s diagnosed and treated.

Dilated cardiomyopathy usually develops when there’s been some damage to the heart muscle. The following conditions may lead to DCM:

Other causes include:

  • exposure to certain toxins, including lead
  • exposure to drugs such as cocaine, methamphetamine, and alcohol
  • certain cancer treatment medications

While it’s not always clear what causes DCM, there are some established risk factors.

Alcohol misuse

Chronic alcohol misuse is an especially significant cause of DCM in males between the ages of 30 and 55.

Alcohol-related DCM accounts for nearly 7% of all cardiomyopathy deaths globally, according to a 2019 report.


Having a parent with DCM increases the chances you may develop this condition. An estimated 20% to 50% of DCM cases are due to genetic factors.

Male sex

Though dilated cardiomyopathy can affect anyone, it is more common in males than females, according to a 2021 study. This difference may be due to the way sex hormones such as estrogen and testosterone affect the heart.

Certain genes that are influenced by estrogen help promote heart tissue repair. This protective function may decrease the risk of cardiac fibrosis — scarring and weakening of the heart muscle. Cardiac fibrosis is a contributing factor to DCM.

In its early stages, DCM may cause no symptoms. But over time, the following signs and symptoms of heart failure may develop:


If you have any of these symptoms, be sure to make an appointment with your doctor. However, if you experience sudden and severe chest pain that lasts a few minutes or difficulty breathing, call 911 or go to the closest emergency room immediately.

Diagnosing DCM usually involves a combination of a physical examination, blood tests, and imaging.

For your physical examination, your doctor will listen to your heart and lungs with a stethoscope to assess your cardiovascular health and fluid status. They will also listen for signs of anything suspicious, such as valve disease or heart failure.

Blood tests can help check for infections and conditions such as diabetes, which may be contributing to DCM or other heart problems.

The primary imaging test used to diagnose DCM is an echocardiogram, which uses sound waves to create moving images of the beating heart. An echocardiogram shows blood flowing through the valves and chambers. The test can also reveal whether the left ventricle has become stretched.

Other imaging tests used to diagnose DCM include:

  • Cardiac catheterization: Cardiac catheterization uses a catheter to reach the heart, where it administers a special dye that can be easily viewed on X-rays that show how well blood is flowing through the coronary arteries and valves.
  • Cardiac magnetic resonance imaging (MRI): A heart MRI uses magnetic fields and radio waves to produce images of the heart’s ventricles and atria (upper chambers).
  • Chest X-ray: A chest X-ray can show whether there is fluid around the lungs, which is a sign of heart failure.
  • Electrocardiogram (ECG): An electrocardiogram (ECG) is another noninvasive test that measures the electrical activity of the heart to check for arrhythmias or reductions in blood flow.

In some cases, treating the underlying cause of dilated cardiomyopathy can reduce DCM symptoms and improve the health and function of the left ventricle. For example, if high blood pressure is the cause of DCM, maintaining a healthy blood pressure may help ease DCM symptoms and complications.

Typically, DCM treatment follows the treatment guidelines for heart failure. This includes the use of heart failure “pillar” drugs that don’t only treat high blood pressure but may improve mortality by helping the heart to rest, repair, and heal. These drugs include:

Additionally, loop diuretics may be used to lower blood pressure and reduce fluid levels in the body. Examples of these include:

For some individuals, device therapy may be necessary to strengthen and protect the heart. Examples of this include an implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy (CRT).

Individuals with DCM and certain arrhythmias or a mechanical artificial heart valve should also take anticoagulant medication to reduce the risk of blood clots forming.

If DCM has resulted in severe heart failure, then the implantation of a left ventricular assist device (LVAD) may be necessary. This helps a weakened heart to pump blood throughout the body.

LVAD is often used as a bridge to a heart transplant, but in recent years, LVAD technology has proven to be reliable enough that many people use LVAD permanently.

If DCM has led to severe heart failure, it may be necessary to have a heart transplant.

However, the overall prognosis for people diagnosed with DCM continues to improve, provided they receive a proper diagnosis and the correct treatment.

Research in 2021 suggests that about 15% of individuals with DCM who receive proper treatment experience a return to healthy left ventricle size and function, and this number may increase with newer heart failure therapies.

Additionally, with treatment, more than 80% of individuals are able to survive without the need for a heart transplant.

In people with dilated cardiomyopathy (DCM), the heart’s left ventricle has grown weaker and larger, forcing the heart to work harder to pump enough blood throughout the body.

DCM can be due to damage to the heart muscle or a genetic condition that puts the heart at risk.

Getting a diagnosis and treatment plan in place earlier can often extend longevity and improve quality of life.