Dilated Cardiomyopathy

Dilated cardiomyopathy is a disease where the heart muscle stretches and weakens, making it harder for the heart to pump blood effectively throughout the body. While some people may not notice symptoms at first, this condition can become life-threatening and is a common cause of heart failure.

Table of contents

• What Is Dilated Cardiomyopathy?
• Parts of the Heart Affected
• Symptoms
• Causes and Risk Factors
• Possible Complications
• How It Is Diagnosed
• Treatment Options
• Living With Dilated Cardiomyopathy
• Outlook and Prognosis

What Is Dilated Cardiomyopathy?

Dilated cardiomyopathy is a type of heart muscle disease that causes the heart chambers, called ventricles (the main pumping chambers of the heart), to thin and stretch, growing larger than normal. This condition typically starts in the heart’s main pumping chamber, known as the left ventricle.^[1]

When the heart muscle stretches out, the tissue in the left ventricle becomes enlarged and then thins. This causes the heart to pump with less force than it should. After each heartbeat, more blood remains in the heart, making it increasingly difficult to keep up with the body’s needs.^[2]

Dilated cardiomyopathy is defined by the presence of left ventricular ejection fraction (a measurement of how much blood the heart pumps out with each beat) of less than 40%. By definition, patients have problems with the heart’s pumping action and may or may not have clear symptoms of heart failure.^[3]

This condition affects about 36 people per 100,000 in the general population. It is the most common form of cardiomyopathy and can develop at any age, though it most often appears in middle age. Dilated cardiomyopathy occurs more frequently in men than in women, and is twice as common in people of African ancestry compared to White people.^[2][13]

• Heart
• Left ventricle
• Right ventricle
• Heart muscle (myocardium)
• Heart valves

Symptoms

Many people with dilated cardiomyopathy don’t have any symptoms, especially in the early stages of the disease. Some people may never experience symptoms at first. However, as heart function worsens over time, symptoms may appear and become more noticeable.^[1][2]

The symptoms of dilated cardiomyopathy can mimic other health conditions. Common signs and symptoms may include:^[1][2]

• Fatigue (feeling very tired or weak)
• Shortness of breath, called dyspnea, during activity or while lying down
• Reduced ability to exercise
• Swelling, called edema, in the legs, ankles, feet, or belly
• Chest pain or discomfort
• Fast, fluttering, or pounding heartbeat (called palpitations)
• Cough and congestion
• Dizziness or feeling lightheaded
• Fainting
• Unexpected weight gain from fluid retention

If you are short of breath or have other symptoms of dilated cardiomyopathy, see your healthcare provider as soon as possible. Call emergency services immediately if you have chest pain that lasts more than a few minutes or have severe difficulty breathing.^[1]

Causes and Risk Factors

In many cases, experts don’t know the exact cause of dilated cardiomyopathy. When no clear cause can be identified, it is called idiopathic dilated cardiomyopathy. The diagnosis of idiopathic dilated cardiomyopathy can only be made after excluding all other possible secondary causes.^[3]

Dilated cardiomyopathy can have many known causes, including:^[2][4]

• Heart disease caused by narrowing or blockage in the coronary arteries
• Poorly controlled high blood pressure
• Genes passed from a biological parent (familial dilated cardiomyopathy), which may account for more than 50% of cases
• Heart attack
• Alcohol use disorder or heavy alcohol use for a prolonged time
• Recreational drugs like cocaine
• Certain chemotherapy drugs that can be toxic to the heart
• Complications in the late stages of pregnancy or shortly after childbirth (called peripartum cardiomyopathy)
• Viral infections, including those that cause myocarditis (inflammation of the heart muscle)
• Infections such as Chagas disease or Lyme disease
• HIV infection
• Diabetes
• Thyroid disease
• Abnormal heart rhythms (called arrhythmia)
• Heart valve disease
• Congenital heart disease (heart problems present from birth)
• Autoimmune illnesses
• Exposure to heavy metals such as lead, arsenic, cobalt, or mercury
• Thiamin deficiency (which can cause a condition called beriberi)

Some people have more than one cause. For example, a person can be at risk because of genetics and then develop a medical condition that leads to dilated cardiomyopathy.^[2]

You may be at higher risk for dilated cardiomyopathy if you:^[2]

• Are younger than 50 years old
• Are Black
• Are male
• Have dilated cardiomyopathy in your biological family

Possible Complications

Untreated dilated cardiomyopathy can lead to heart failure, which is a serious condition where the heart doesn’t pump enough blood for the body’s needs. In advanced stages, dilated cardiomyopathy can lead to several other complications.^[1][2]

These complications may include:^[2][14]

• Heart failure
• Abnormal heart rhythms (arrhythmia)
• Heart valve disease
• Blood clots in the heart, which can travel to the lungs and become a pulmonary embolism
• Stroke
• Heart attack
• Cardiac arrest (when the heart stops beating suddenly and unexpectedly)
• Cardiogenic shock (a life-threatening condition where the heart can’t pump enough blood and oxygen to the brain, kidneys, and other important organs)
• Angina (chest pain)

How It Is Diagnosed

To diagnose dilated cardiomyopathy, your healthcare provider will do a physical exam and ask questions about your personal and family medical history. If a family member has dilated cardiomyopathy, talk to your healthcare provider, as some types of the condition run in families. The provider will use a device called a stethoscope to listen to your heart and lungs. Your provider may hear a heart murmur before you even have symptoms.^[2][7]

Tests to diagnose dilated cardiomyopathy include:^[2][7]

• Echocardiogram: This is the main test for diagnosing dilated cardiomyopathy. Sound waves produce images of the heart in motion. An echocardiogram shows how blood moves in and out of the heart and heart valves. It can tell if the left ventricle is enlarged.
• Electrocardiogram (EKG or ECG): This quick and easy test records the electrical activity of the heart. It can show how fast or slow the heart is beating and help diagnose heart rhythm problems or reduced blood flow.
• Chest X-ray: This test shows the shape and condition of the heart and lungs. It can reveal fluid in or around the lungs.
• Blood tests: Different blood tests can check for infections, substances, or diseases that may lead to dilated cardiomyopathy. A test that checks for heart damage may be done.
• Holter monitor: This portable device can be worn for a day or more to record the heart’s activity during daily activities.
• Exercise stress test: This test often involves walking on a treadmill or riding a stationary bike while the heart is monitored. If you can’t exercise, you might be given medications that mimic the effect of exercise on the heart.
• Cardiac catheterization (also called an angiogram): This test looks for narrow areas in the coronary arteries, which send blood to the heart.
• Cardiac CT or MRI scan: These imaging tests can show the size and function of the heart’s pumping chambers.
• Heart biopsy: In this test, a small piece of heart muscle is removed and examined. This is rarely done, but may be needed depending on the cause.

Testing will determine the severity of the condition and help healthcare providers plan your treatment.^[2]

Treatment Options

The goal of treatment is to slow the disease, help you feel better, and prevent complications. Treatment is directed at the cause when possible. You may also have treatment for conditions that worsen dilated cardiomyopathy, such as high blood pressure or diabetes.^[4][9]

Most people with dilated cardiomyopathy need to take medicines. Treatment often includes medications such as:^[4][9][10]

• Angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs): These medicines make it easier for blood to flow and can help the heart work better.
• Beta-blockers: These medicines slow the heart rate and can help the heart fill with blood more completely.
• Aldosterone antagonists (also called mineralocorticoid receptor antagonists): These medicines help remove excess fluid and have other benefits for heart function.
• Angiotensin receptor-neprilysin inhibitor (ARNI): This combination medicine has been shown to be superior to ACE inhibitors in reducing cardiovascular death and hospitalization from heart failure.
• Diuretics: These medicines help remove excess fluid from the body and can reduce swelling.
• Cardiac glycosides (such as digoxin): These medicines can help the heart pump more strongly.
• Blood thinners: These medicines may be recommended if you have certain types of irregular heartbeat to prevent blood clots.

If your doctor thinks it will help your heart and prevent problems, you may need a device such as:^[9][10]

• Pacemaker: This device helps treat slow heart rates or helps your heartbeat stay in sync.
• Implantable cardioverter-defibrillator (ICD): This device recognizes life-threatening heart rhythms and sends an electrical pulse (shock) to stop them.
• Cardiac resynchronization therapy (CRT): This special type of pacemaker may be needed if you have persistent pumping problems and severe delays in the heart’s electrical conduction system.

If heart failure is progressive and severe, other procedures may be needed:^[9][10]

• Heart bypass surgery or angioplasty if coronary artery disease is present
• Repair of moderate to severe valve problems
• Left ventricular assist device (LVAD): This mechanical pump can help your heart pump blood if you have severe heart failure
• Heart transplantation: This may be an option in some cases if other measures are not effective

Living With Dilated Cardiomyopathy

Self-care is an important part of your treatment. Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your healthcare provider if you are having problems.^[18]

Heart-healthy lifestyle changes you can make include:^[14][15][18]

• Be active. Exercise regularly, but don’t exercise too hard. Talk to your doctor before starting an exercise program to make sure it is safe for you.
• Do not smoke. Smoking can make a heart condition worse. If you need help quitting, talk to your doctor about stop-smoking programs and medicines.
• Eat a heart-healthy diet.
• Stay at a healthy weight. Lose weight if you need to.
• If your doctor recommends it, limit sodium (salt). This helps keep fluid from building up in your body and may help you feel better.
• Manage other health problems, including diabetes, high blood pressure, and high cholesterol.
• Limit alcohol consumption or avoid alcohol completely.
• Get vaccinated against COVID-19, influenza (flu), and pneumonia.
• If you think you may have a problem with alcohol or drug use, talk to your doctor.

Weigh yourself without clothing at the same time each day. Record your weight. Call your doctor if you have a sudden weight gain, such as more than 1 to 1.3 kilograms (2 to 3 pounds) in a day or 2.3 kilograms (5 pounds) in a week. A sudden weight gain may mean that your condition is getting worse.^[18]

Be safe with medicines. Take your medicines exactly as prescribed. Call your doctor if you think you are having a problem with your medicine. It’s also a good idea to keep a list of the medicines you take.^[18]

If you have been diagnosed with dilated cardiomyopathy, your blood relatives may also need to be checked, as the condition often runs in families. First-degree relatives may need periodic clinical and imaging evaluations, and genetic testing may be recommended.^[9]

Outlook and Prognosis

About 1 per 2,500 people is affected by dilated cardiomyopathy. The five-year survival rate is about 50%, though this varies greatly depending on many factors.^[6]

With appropriate medical intervention, treatment, and follow-up, prospects are very favorable for an extended life after a dilated cardiomyopathy diagnosis. Each case is unique, and there are many factors that may increase or decrease long-term survival. Most essential to long-term survival is the skillful use of medical therapy and devices when needed.^[22]

Nowadays, pharmacological and non-pharmacological therapies have dramatically changed the natural history of dilated cardiomyopathy. Patients affected by dilated cardiomyopathy may or may not develop clear heart failure and irregular heart rhythms. Sudden cardiac death can occur at any stage of the disease.^[9]

Without medical intervention, regular doctor visits, and appropriate treatment, the prospects for long-term survival are poor. However, with proper care, many patients live long, fulfilling lives after their diagnosis.^[22]