Cardiomyopathy

Types of Cardiomyopathy and Their Causes

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.

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.

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

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.

Dilated cardiomyopathy can be caused by:

• 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

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.

Restrictive cardiomyopathy can be caused by certain diseases, conditions, and factors, 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

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. The disease is thought to be inherited.

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.

Risk Factors for Cardiomyopathy

Certain diseases, conditions, or factors can raise your risk for cardiomyopathy, including:

• 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.

Diagnosing Cardiomyopathy

Your doctor will diagnose cardiomyopathy based on your medical and family histories, a physical exam, and the results from tests and procedures. Often, a cardiologist or pediatric cardiologist diagnoses and treats cardiomyopathy. 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.

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

• blood test
• chest X-ray
• EKG (electocardiogram)
• Holter monitoring
• echocardiography (echo)
• stress test
• nuclear heart scanning
• positron emission tomography (PET) scanning

In addition, you may have one or more medical procedures to confirm the diagnosis or to prepare for surgery, if planned including: 

• cardiac catheterization
• coronary angioplasty
• myocardial biopsy

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 and 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

Surgery and Implanted Devices

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

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.

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.
• Alcohol septal ablation is a non-surgical procedure where 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.

Make an Appointment With a Cardiac Partners Cardiomyopathy Specialist

To make an appointment with a Cardiac Partners physician or to schedule diagnostic testing, call 833-SJHEART (833-754-3278)