Dilated cardiomyopathy (DCM) occurs when the ventricles of the heart dilate and weaken, reducing the heart’s ability to pump enough blood.

DCM is a severe heart condition that often begins in the left ventricle, the heart’s main pumping chamber. Its enlargement impairs the heart’s ability to pump blood efficiently and meet the body’s demands. Eventually, a person can experience heart failure and other complications.

Doctors link the causes of DCM to genetics, environmental factors, and other underlying health conditions.

This article covers the causes, symptoms, and diagnosis of DCM and how people with this heart condition can improve their quality of life.

A technician performing an ultrasound scan on a man's chest to look for signs of cardiomyopathy.Share on Pinterest
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DCM is a condition that affects the heart muscle. It occurs when the muscle weakens and the main pumping chambers, or ventricles, become enlarged and stretched. This means the heart muscle cannot contract strongly enough to pump blood efficiently.

Doctors evaluate DCM by measuring left ventricular ejection fraction (LVEF). In DCM, the LVEF is less than 40%. As a result, some people with DCM experience symptoms of heart failure, though others might not have any symptoms.

DCM can be primary or secondary. Primary DCM occurs on its own for unknown reasons. Secondary DCM is a result of another condition, such as heart disease or infection.

DCM usually begins causing symptoms in people between 20 and 60 years old. It can also occur in older adults and children.

Often, doctors cannot determine the cause of DCM, but several factors are known to contribute to its development:

  • Genetic inheritance: Some people may have a genetic predisposition to developing DCM. In some cases, it may occur due to genetic changes that affect heart muscle proteins.
  • Viral infections: Certain viral infections, including HIV and hepatitis, can lead to myocarditis, which can evolve into DCM.
  • Alcohol and toxins: Long-term heavy alcohol use and exposure to certain toxins, including chemotherapy drugs, can damage heart muscle.
  • Autoimmune diseases: Conditions where the immune system attacks the body’s own tissues can also affect the heart.
  • Metabolic disorders: Diabetes and thyroid disorders can contribute to the development of DCM.

DCM is also more common in males than females and in Black people than white people.

Researchers are still learning why DCM is more common in males and highlight the need for more studies.

Because Black people also have worse outcomes and lower survival rates with DCM, experts believe that health inequity is a key factor in explaining this disparity.

The symptoms of DCM may develop gradually or suddenly and can vary widely among individuals. Symptoms can include:

  • breathlessness when active or lying down
  • fatigue and weakness
  • swelling in the legs, ankles, and feet
  • irregular heartbeats that feel rapid, pounding, or fluttering
  • chest pain or discomfort
  • dizziness, lightheadedness, and fainting

Doctors classify the progression of symptoms into four stages:

  • Stage A: A person has risk factors for DCM but no symptoms.
  • Stage B: A person has no symptoms but does have clinical signs of ventricular dysfunction, heart valve disease, heart failure, or previous myocardial infarction.
  • Stage C: A person has symptoms and a limitation in physical activities. Mild exertion, such as walking short distances, may lead to shortness of breath and fatigue.
  • Stage D: A person has severe symptoms that occur while at rest despite admissions to the hospital and thorough medical treatment.

Diagnosing DCM involves a doctor taking a person’s medical history, performing a physical examination, and running tests. These tests may include:

DCM treatment focuses on both managing acute symptoms and maintaining long-term heart health. Strategies may involve:

  • Intravenous (IV) diuretics: In acute cases, doctors administer IV diuretics to reduce blood volume overload and alleviate symptoms quickly.
  • Medications: Doctors use a range of oral medications to help people with chronic DCM. They include angiotensin converting enzyme inhibitors to improve heart function, beta-blockers to slow the progression of heart failure, and oral diuretics to help maintain normal blood volume.
  • Anticoagulants: People with atrial fibrillation, artificial heart valves, or mural thrombus typically receive oral anticoagulants to reduce the risk of stroke.
  • Lifestyle changes: These can include dietary changes, such as limiting salt and water, to reduce symptoms. Doctors also encourage people to abstain from drinking alcohol and smoking and remain physically active where possible.
  • Device implantation: These devices include pacemakers or defibrillators to manage heart rhythm and support heart function.
  • Heart transplant: In severe cases, doctors may consider a heart transplant when other treatments have not worked.

People with DCM can enroll in a cardiac rehabilitation program. This is a structured program that helps people with diet, exercise, and understanding their condition. With regular participation, cardiac rehabilitation can lower the risk of death by 20%.

The outlook for people with DCM is guarded. It is a serious condition that can potentially lead to life threatening complications.

Many people with DCM eventually develop chronic heart failure. A significant number may need a heart transplant or a device to help their heart function.

Around 50% of people with DCM die within 5 years of their diagnosis. Several factors have links to a worse outlook, including:

  • being in an advanced stage of heart failure
  • having severe heart failure symptoms
  • experiencing kidney failure
  • being male

These factors do not guarantee a less favorable outlook, though.

With adequate medical treatment, people with mild heart failure symptoms can still enjoy a relatively good quality of life.

Individuals with DCM need to make significant lifestyle adjustments and maintain rigorous health management routines to effectively manage their symptoms and slow the disease’s progression.

Here are some of the important components of living with DCM:

  • Regular medical follow-ups: Continual and regular checkups with healthcare professionals are essential. These appointments allow doctors to closely monitor the heart’s function, adjust medications, and promptly manage any complications that may arise.
  • Adherence to treatment plans: Follow the prescribed treatment plan. This includes taking all medications as directed and communicating with the healthcare team about any side effects or concerns.
  • Lifestyle changes: Adopt a heart-healthy diet low in sodium and rich in fruits, vegetables, lean proteins, and whole grains. Follow a cardiologist’s recommendations for exercise, and if relevant, quit smoking or drinking alcohol.
  • Stress management: Reducing stress can also help manage symptoms of DCM by lowering blood pressure and improving overall heart health.
  • Support systems: Building a solid support network of family, friends, and support groups can provide emotional assistance and practical help in managing DCM. People may find it helpful to share experiences and strategies with others who have similar challenges.

Dilated cardiomyopathy (DCM) is a complex condition that impairs the heart’s ability to pump blood efficiently, potentially leading to heart failure.

Treatment may involve a combination of prescription treatments, lifestyle changes, and, in severe cases, surgical interventions. The effectiveness of these treatments and proactive disease management can substantially improve a person’s outlook and quality of life.