Cardiomyopathy

Cardiomyopathy refers to diseases of the heart muscle. These diseases have many causes, signs and symptoms, and treatments. In cardiomyopathy, the heart muscle becomes enlarged, thick, or rigid. In rare cases, the muscle tissue in the heart is replaced with scar tissue.

As cardiomyopathy worsens, the heart becomes weaker. It’s less able to pump blood through the body and maintain a normal electrical rhythm. This can lead to heart failure or irregular heartbeats called arrhythmias. In turn, heart failure can cause fluid to build up in the lungs, ankles, feet, legs, or abdomen.

The weakening of the heart also can cause other complications, such as heart valve problems.

Overview

The types of cardiomyopathy are:

• Hypertrophic cardiomyopathy
• Dilated cardiomyopathy
• Restrictive cardiomyopathy
• Arrhythmogenic right ventricular dysplasia
• Unclassified cardiomyopathy

Cardiomyopathy can be acquired or inherited. “Acquired” means you aren’t born with the disease, but you develop it due to another disease, condition, or factor. “Inherited” means your parents passed the gene for the disease on to you. Many times, the cause of cardiomyopathy isn’t known.

Cardiomyopathy can affect people of all ages. However, people in certain age groups are more likely to have certain types of cardiomyopathy. This article focuses on cardiomyopathy in adults.

Types of Cardiomyopathy

Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy is very common and can affect people of any age. Hypertrophic cardiomyopathy affects men and women equally, and about 1 out of every 500 people has the disease.

Hypertrophic cardiomyopathy happens when the heart muscle enlarges and thickens without an obvious cause. Usually the ventricles, the lower chambers of the heart, and septum (the wall that separates the left and right side of the heart) thicken. The thickened areas create narrowing or blockages in the ventricles, making it harder for the heart to pump blood. Hypertrophic cardiomyopathy also can cause stiffness of the ventricles, changes in the mitral valve, and cellular changes in the heart tissue. The disease is also referred to as;

• Asymmetric septal hypertrophy
• Familial hypertrophic cardiomyopathy
• Hypertrophic nonobstructive cardiomyopathy
• Hypertrophic obstructive cardiomyopathy
• Idiopathic hypertrophic subaortic stenosis

Dilated Cardiomyopathy

Dilated cardiomyopathy develops when the ventricles enlarge and weaken. The condition usually starts in the left ventricle and over time can affect the right ventricle. The weakened chambers of the heart don’t pump effectively, causing the heart muscle to work harder. Over time, the heart loses the ability to pump blood effectively. Dilated cardiomyopathy can lead to heart failure, heart valve disease, irregular heart rate, and blood clots in the heart. This disease is also referred to as;

• Alcoholic cardiomyopathy. This term is used when overuse of alcohol causes the disease.
• Congestive cardiomyopathy.
• Diabetic cardiomyopathy.
• Familial dilated cardiomyopathy.
• Idiopathic cardiomyopathy.
• Ischemic cardiomyopathy. This term is used when ischemic heart disease (also called coronary artery disease) or heart attack causes the disease.
• Peripartum cardiomyopathy. This term is used when the disease develops in a woman shortly before or after she gives birth.
• Primary cardiomyopathy.

Restrictive Cardiomyopathy

Restrictive cardiomyopathy develops when the ventricles become stiff and rigid but the walls of the heart do not thicken. As a result, the ventricles do not relax and don’t fill with the normal blood volume. As the disease progresses, the ventricles do not pump as well and the heart muscle weakens. Over time, restrictive cardiomyopathy can lead to heart failure and problems with the heart valves. This disease is also referred to as;

• Idiopathic restrictive cardiomyopathy
• Infiltrative cardiomyopathy

Arrhythmogenic Right Ventricular Dysplasia

Arrhythmogenic right ventricular dysplasia is a rare type of cardiomyopathy that occurs when the muscle tissue in the right ventricle is replaced with fatty or fibrous tissue. This can lead to disruptions in the heart’s electrical signals and causes arrhythmias. Arrhythmogenic right ventricular dysplasia usually affects teens or young adults and can cause sudden cardiac arrest in young athletes. This disease is also referred to as;

• Arrhythmogenic right ventricular cardiomyopathy
• Right ventricular cardiomyopathy
• Right ventricular dysplasia

Unclassified Cardiomyopathy

Other types of cardiomyopathy are grouped into this category and can include:

• Left ventricular noncompaction happens when the left ventricle has trabeculations, projections of muscle inside the ventricle.
• Takotsubo cardiomyopathy, or broken heart syndrome, happens when extreme stress leads to heart muscle failure. Though rare, this condition is more common in post-menopausal women.

Causes of Cardiomyopathy

Cardiomyopathy can be acquired or inherited. “Acquired” means you aren’t born with the disease, but you develop it due to another disease, condition, or factor.

“Inherited” means your parents passed the gene for the disease on to you. Researchers continue to look for the genetic links to cardiomyopathy and to explore how these links cause or contribute to the various types of the disease.

Many times, the cause of cardiomyopathy isn’t known. This often is the case when the disease occurs in children.

Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy usually is inherited. It’s caused by a mutation or change in some of the genes in heart muscle proteins. Hypertrophic cardiomyopathy also can develop over time because of high blood pressure, aging, or other diseases, such as diabetes or thyroid disease. Sometimes the cause of the disease isn’t known.

Dilated Cardiomyopathy

The cause of dilated cardiomyopathy often isn’t known. About one-third of the people who have dilated cardiomyopathy inherit it from their parents.

Certain diseases, conditions, and substances also can cause the disease, such as:

• Alcohol, especially if you also have a poor diet
• Certain toxins, such as poisons and heavy metals
• Complications during the last months of pregnancy
• Ischemic heart disease, heart attack, high blood pressure, diabetes, thyroid disease, viral hepatitis, and HIV
• Illegal drugs, such as cocaine and amphetamines, and some medicines used to treat cancer
• Infections, especially viral infections that inflame the heart muscle

Restrictive Cardiomyopathy

Certain diseases, conditions, and factors can cause restrictive cardiomyopathy, including:

• Amyloidosis: A disease in which abnormal proteins build up in the body’s organs, including the heart
• Connective tissue disorders
• Hemochromatosis: A disease in which too much iron builds up in the body. The extra iron is toxic to the body and can damage the organs, including the heart.
• Sarcoidosis: A disease that causes inflammation and can affect various organs in the body. Researchers believe that an abnormal immune response may cause sarcoidosis. This abnormal response causes tiny lumps of cells to form in the body’s organs, including the heart.
• Some cancer treatments, such as radiation and chemotherapy

Arrhythmogenic Right Ventricular Dysplasia

Researchers think that arrhythmogenic right ventricular dysplasia is an inherited disease.

Risk Factors for Cardiomyopathy

People of all ages and races can have cardiomyopathy. However, certain types of the disease are more common in certain groups.

Dilated cardiomyopathy is more common in African Americans than Whites. This type of the disease also is more common in men than women.

Teens and young adults are more likely than older people to have arrhythmogenic right ventricular dysplasia, although it’s rare in both groups.

Major Risk Factors

Certain diseases, conditions, or factors can raise your risk for cardiomyopathy. Major risk factors include:

• A family history of cardiomyopathy, heart failure, or sudden cardiac arrest (SCA)
• A disease or condition that can lead to cardiomyopathy, such as ischemic heart disease, heart attack, or a viral infection that inflames the heart muscle
• Diabetes or other metabolic diseases, or severe obesity
• Diseases that can damage the heart, such as hemochromatosis, sarcoidosis, or amyloidosis
• Long-term alcoholism
• Long-term high blood pressure

Some people who have cardiomyopathy never have signs or symptoms. Thus, it’s important to identify people who may be at high risk for the disease. This can help prevent future problems, such as serious arrhythmias (irregular heartbeats) or SCA.

Signs, Symptoms, and Complications- Cardiomyopathy

Some people who have cardiomyopathy never have signs or symptoms. Others don’t have signs or symptoms in the early stages of the disease.

As cardiomyopathy worsens and the heart weakens, signs and symptoms of heart failure usually occur. These signs and symptoms include:

• Shortness of breath or trouble breathing, especially with physical exertion
• Fatigue (tiredness)
• Swelling in the ankles, feet, legs, abdomen, and veins in the neck

Other signs and symptoms may include dizziness; light-headedness; fainting during physical activity; arrhythmias (irregular heartbeats); chest pain, especially after physical exertion or heavy meals; and heart murmurs. (Heart murmurs are extra or unusual sounds heard during a heartbeat.)

Diagnosing Cardiomyopathy

Your doctor will diagnose cardiomyopathy based on your medical and family histories, a physical exam, and the results from tests and procedures.

Specialists Involved

Often, a cardiologist or pediatric cardiologist diagnoses and treats cardiomyopathy. A cardiologist specializes in diagnosing and treating heart diseases. A pediatric cardiologist is a cardiologist who treats children.

Medical and Family Histories

Your doctor will want to learn about your medical history. He or she will want to know what signs and symptoms you have and how long you’ve had them.

Your doctor also will want to know whether anyone in your family has had cardiomyopathy, heart failure, or sudden cardiac arrest.

Physical Exam

Your doctor will use a stethoscope to listen to your heart and lungs for sounds that may suggest cardiomyopathy. These sounds may even suggest a certain type of the disease.

For example, the loudness, timing, and location of a heart murmur may suggest obstructive hypertrophic cardiomyopathy. A “crackling” sound in the lungs may be a sign of heart failure. (Heart failure often develops in the later stages of cardiomyopathy.)

Physical signs also help your doctor diagnose cardiomyopathy. Swelling of the ankles, feet, legs, abdomen, or veins in your neck suggests fluid buildup, a sign of heart failure.

Your doctor may notice signs and symptoms of cardiomyopathy during a routine exam. For example, he or she may hear a heart murmur, or you may have abnormal test results.

Diagnostic Tests

Your doctor may recommend one or more of the following tests to diagnose cardiomyopathy.

Blood Tests

During a blood test, a small amount of blood is taken from your body. It’s often drawn from a vein in your arm using a needle. The procedure usually is quick and easy, although it may cause some short-term discomfort.

Blood tests give your doctor information about your heart and help rule out other conditions.

Chest X Ray

A chest x ray takes pictures of the organs and structures inside your chest, such as your heart, lungs, and blood vessels. This test can show whether your heart is enlarged. A chest x ray also can show whether fluid is building up in your lungs.

EKG (Electrocardiogram)

An EKG is a simple test that records the heart’s electrical activity. The test shows how fast the heart is beating and its rhythm (steady or irregular). An EKG also records the strength and timing of electrical signals as they pass through each part of the heart.

This test is used to detect and study many heart problems, such as heart attacks, arrhythmias (irregular heartbeats), and heart failure. EKG results also can suggest other disorders that affect heart function. A standard EKG only records the heartbeat for a few seconds. It won’t detect problems that don’t happen during the test.

To diagnose heart problems that come and go, your doctor may have you wear a portable EKG monitor. The two most common types of portable EKGs are Holter and event monitors.

Holter and Event Monitors

Holter and event monitors are small, portable devices. They record your heart’s electrical activity while you do your normal daily activities. A Holter monitor records the heart’s electrical activity for a full 24- or 48-hour period.

An event monitor records your heart’s electrical activity only at certain times while you’re wearing it. For many event monitors, you push a button to start the monitor when you feel symptoms. Other event monitors start automatically when they sense abnormal heart rhythms.

Echocardiography

Echocardiography (echo) is a test that uses sound waves to create a moving picture of your heart. The picture shows how well your heart is working and its size and shape.

There are several types of echo, including stress echo. This test is done as part of a stress test (see below). Stress echo can show whether you have decreased blood flow to your heart, a sign of coronary heart disease.

Another type of echo is transesophageal echo, or TEE. TEE provides a view of the back of the heart.

For this test, a sound wave wand is put on the end of a special tube. The tube is gently passed down your throat and into your esophagus (the passage leading from your mouth to your stomach). Because this passage is right behind the heart, TEE can create detailed pictures of the heart’s structures.

Before TEE, you’re given medicine to help you relax, and your throat is sprayed with numbing medicine.

Stress Test

Some heart problems are easier to diagnose when your heart is working hard and beating fast. During stress testing, you exercise (or are given medicine if you’re unable to exercise) to make your heart work hard and beat fast while heart tests are done.

These tests may include nuclear heart scanning, echo, and positron emission tomography (PET) scanning of the heart.

Diagnostic Procedures

You may have one or more medical procedures to confirm a diagnosis or to prepare for surgery (if surgery is planned). These procedures may include cardiac catheterization, coronary angiography, or myocardial biopsy.

Cardiac Catheterization

This procedure checks the pressure and blood flow in your heart’s chambers. The procedure also allows your doctor to collect blood samples and look at your heart’s arteries using x-ray imaging.

During cardiac catheterization, a long, thin, flexible tube called a catheter is put into a blood vessel in your arm, groin (upper thigh), or neck and threaded to your heart. This allows your doctor to study the inside of your arteries for blockages.

Coronary Angiography

This procedure often is done with cardiac catheterization. During the procedure, dye that can be seen on an x ray is injected into your coronary arteries. The dye lets your doctor study blood flow through your heart and blood vessels.

Dye also may be injected into your heart chambers. This allows your doctor to study the pumping function of your heart.

Myocardial Biopsy

For this procedure, your doctor removes a piece of your heart muscle. This can be done during cardiac catheterization. The heart muscle is studied under a microscope to see whether changes in cells have occurred. These changes may suggest cardiomyopathy.

Myocardial biopsy is useful for diagnosing some types of cardiomyopathy.

Genetic Testing

Some types of cardiomyopathy run in families. Thus, your doctor may suggest genetic testing to look for the disease in your parents, brothers and sisters, or other family members.

Genetic testing can show how the disease runs in families. It also can find out the chances of parents passing the genes for the disease on to their children.

Genetic testing also may be useful if your doctor thinks you have cardiomyopathy, but you don’t yet have signs or symptoms. If the test shows you have the disease, your doctor can start treatment early, when it may work best.

Treating Cardiomyopathy

People who have cardiomyopathy but no signs or symptoms may not need treatment. Sometimes, dilated cardiomyopathy that comes on suddenly may go away on its own. For other people who have cardiomyopathy, treatment is needed. Treatment depends on the type of cardiomyopathy you have, the severity of your symptoms and complications, and your age and overall health. Treatments may include:

• Heart-healthy lifestyle changes
• Medicines
• Nonsurgical procedure
• Surgery and implanted devices

The main goals of treating cardiomyopathy include:

• Controlling signs and symptoms so that you can live as normally as possible
• Managing any conditions that cause or contribute to the disease
• Reducing complications and the risk of sudden cardiac arrest
• Stopping the disease from getting worse

Heart-Healthy Lifestyle Changes

Your doctor may suggest lifestyle changes to manage a condition that’s causing your cardiomyopathy including:

• Heart-healthy eating
• Aiming for a healthy weight
• Managing stress
• Physical activity
• Quitting smoking

Medicines

Many medicines are used to treat cardiomyopathy. Your doctor may prescribe medicines to:

• Balance electrolytes in your body. Electrolytes are minerals that help maintain fluid levels and acid-base balance in the body. They also help muscle and nerve tissues work properly. Abnormal electrolyte levels may be a sign of dehydration (lack of fluid in your body), heart failure, high blood pressure, or other disorders. Aldosterone blockers are an example of a medicine used to balance electrolytes.
• Keep your heart beating with a normal rhythm. These medicines, called antiarrhythmics, help prevent arrhythmias.
• Lower your blood pressure. ACE inhibitors, angiotensin II receptor blockers, beta blockers, and calcium channel blockers are examples of medicines that lower blood pressure.
• Prevent blood clots from forming. Anticoagulants, or blood thinners, are an example of a medicine that prevents blood clots. Blood thinners often are used to prevent blood clots from forming in people who have dilated cardiomyopathy.
• Reduce inflammation. Corticosteroids are an example of a medicine used to reduce inflammation. 
• Remove excess sodium from your body. Diuretics, or water pills, are an example of medicines that help remove excess sodium from the body, which reduces the amount of fluid in your blood.
• Slow your heart rate. Beta blockers, calcium channel blockers, and digoxin are examples of medicines that slow the heart rate. Beta blockers and calcium channel blockers also are used to lower blood pressure.

Take all medicines regularly, as your doctor prescribes. Don’t change the amount of your medicine or skip a dose unless your doctor tells you to.

​Surgery and Implanted Devices

Doctors use several types of surgery to treat cardiomyopathy, including septal myectomy, surgically implanted devices, and heart transplant.

Septal Myectomy

Septal myectomy is open-heart surgery and is used to treat people who have hypertrophic cardiomyopathy and severe symptoms. This surgery generally is used for younger patients and for people whose medicines aren’t working well.

A surgeon removes part of the thickened septum that’s bulging into the left ventricle. This improves blood flow through the heart and out to the body. The removed tissue doesn’t grow back. If needed, the surgeon also can repair or replace the mitral valve at the same time. Septal myectomy often is successful and allows you to return to a normal life with no symptoms.

Surgically Implanted Devices

Surgeons can place several types of devices in the heart to improve function and symptoms, including:

• Cardiac resynchronization therapy (CRT) device. A CRT device coordinates contractions between the heart’s left and right ventricles.
• Implantable cardioverter defibrillator (ICD). An ICD helps control life-threatening arrhythmias that may lead to sudden cardiac arrest. This small device is implanted in the chest or abdomen and connected to the heart with wires. If an ICD senses a dangerous change in heart rhythm, it will send an electric shock to the heart to restore a normal heartbeat.
• Left ventricular assist device (LVAD). This device helps the heart pump blood to the body. An LVAD can be used as a long-term therapy or as a short-term treatment for people who are waiting for a heart transplant.
• Pacemaker. This small device is placed under the skin of your chest or abdomen to help control arrhythmias. The device uses electrical pulses to prompt the heart to beat at a normal rate.

Heart Transplant

For this surgery, a surgeon replaces a person’s diseased heart with a healthy heart from a deceased donor. A heart transplant is a last resort treatment for people who have end-stage heart failure. “End-stage” means the condition has become so severe that all treatments, other than heart transplant, have failed.

Nonsurgical Procedure

Doctors may use a nonsurgical procedure called alcohol septal ablation to treat cardiomyopathy. During this procedure, the doctor injects ethanol (a type of alcohol) through a tube into the small artery that supplies blood to the thickened area of heart muscle. The alcohol kills cells, and the thickened tissue shrinks to a more normal size. This procedure allows blood to flow freely through the ventricle, which improves symptoms.