Cardiomyopathy refers to diseases of the heart muscle. These diseases have a variety of causes, symptoms, and treatments. In cardiomyopathy, the heart muscle becomes enlarged or abnormally thick or rigid. In rare cases, the muscle tissue in the heart is replaced with scar tissue.
Dilated cardiomyopathy is the most common form of cardiomyopathy. It generally occurs in adults aged 20 to 60 years. Men are more likely than women to develop dilated cardiomyopathy.
Dilated cardiomyopathy affects the heart's ventricles (VEN-trih-kuls) and atria. The ventricles are the two lower chambers of the heart, and the atria are the two upper chambers. Dilated cardiomyopathy usually starts in the left ventricle, where the heart muscle begins to dilate or stretch and become thinner. This leads to enlargement of the inside of the ventricle. The problem often spreads to the right ventricle and then to the atria as the disease gets worse.
When the chambers dilate, the heart can't pump blood very well. The heart tries to cope by dilating the chambers even more. Over time, the heart becomes weaker and heart failure can occur. Symptoms of heart failure include feeling tired, swelling of the legs and feet, and shortness of breath. Dilated cardiomyopathy also can lead to heart valve problems, arrhythmias, and blood clots in the heart. Having advanced dilated cardiomyopathy is a common reason for needing a heart transplant.
Up to one-half of all cases of dilated cardiomyopathy may be hereditary (passed down in the genes from parent to child). These cases are called familial dilated cardiomyopathy. Dilated cardiomyopathy also can be a complication of many conditions, including coronary artery disease and high blood pressure. It also can be caused by viral infections, excessive use of alcohol, and exposure to certain drugs (including cocaine, amphetamines, and some drugs used in cancer treatments). In some cases, no cause can be found.
Hypertrophic cardiomyopathy occurs when the heart muscle thickens abnormally. The thickening generally happens in the left ventricle, the heart's main pumping chamber. This type of cardiomyopathy can affect people of any age.
Hypertrophic cardiomyopathy can be obstructive or nonobstructive. In the obstructive type, the septum (the wall that divides the left and right sides of the heart) thickens and bulges into the left ventricle. This bulge blocks the flow of blood out of the ventricle. The ventricle must work much harder to pump blood past the blockage and out to the body. Symptoms can include chest pain, dizziness, shortness of breath, or fainting.
Obstructive hypertrophic cardiomyopathy also can affect the heart's mitral (MI-trul) valve, causing blood to leak backward through the valve.
In nonobstructive hypertrophic cardiomyopathy, the thickened heart muscle does not block the flow of blood out of the ventricle. The entire ventricle may become thicker (symmetric ventricular hypotrophy) or it may happen only at the bottom of the heart (apical hypertrophy). The right ventricle also may be affected.
In both kinds of hypertrophic cardiomyopathy, the thickened muscle makes the inside of the left ventricle smaller so that it holds less blood. The walls of the ventricles also may become stiff. As a result, they are less able to relax and fill with blood. This causes increased pressure in the ventricles and the blood vessels of the lungs. Changes also occur to the cells in the damaged heart muscle. This may interfere with the heart's electrical signals, leading to arrhythmias.
Some people with hypertrophic cardiomyopathy have no symptoms, and the condition does not affect their lives. Others have severe symptoms or develop complications such as serious arrhythmias. A few people with the condition have sudden cardiac arrest because of dangerous arrhythmias.
Hypertrophic cardiomyopathy can be inherited because of a gene mutation or develop over time because of high blood pressure or aging. Often, the cause is unknown.
Restrictive cardiomyopathy tends to mostly affect older adults. In this cardiomyopathy, the ventricles become stiff and rigid due to replacement of the normal heart muscle with abnormal tissue, such as scar tissue. As a result, the ventricles cannot relax normally and expand to fill with blood, which causes the atria to become enlarged. Eventually, blood flow in the heart is reduced, and complications such as heart failure or arrhythmias occur.
Restrictive cardiomyopathy can occur for no known reason, or it can develop because the person has another disease. Some of the diseases that can cause restrictive cardiomyopathy include hemochromatosis, sarcoidosis, amyloidosis, and connective tissue disorders. Restrictive cardiomyopathy also can occur as a result of radiation treatments, infections, or scarring after surgery.
Arrhythmogenic right ventricular dysplasia (ARVD) is a rare type of cardiomyopathy. ARVD develops when the muscle tissue in the right ventricle dies and is replaced with scar tissue. This process causes problems in the heart's electrical signaling, resulting in arrhythmias. Symptoms include a feeling of strong or irregular heartbeats (palpitations) and fainting after exercise.
ARVD usually develops in teens or young adults and is often the cause of sudden cardiac death in young athletes. ARVD is thought to be an inherited disease.
Many times, the cause of cardiomyopathy is unknown. When this happens, the disease is called idiopathic (or primary) cardiomyopathy. The majority of cardiomyopathies in children are idiopathic.
Sometimes, cardiomyopathy is inherited (passed down in the genes from parent to child) or caused by another disease or condition.
Dilated cardiomyopathy can be inherited. It also can be caused by certain diseases, conditions, and substances, including:
Hypertrophic cardiomyopathy can be inherited. It also can develop over time because of high blood pressure or aging. Often, the cause of hypertrophic cardiomyopathy is unknown.
Certain diseases and conditions can cause restrictive cardiomyopathy, including:
Arrythmogenic right ventricular dysplasia is thought to be an inherited disease.
People of all ages can develop cardiomyopathy, but certain cardiomyopathies are more common in certain groups:
Major risk factors for developing cardiomyopathy include:
Some people with cardiomyopathy never have symptoms. That is why it's important to identify people who may be at high risk for this disease so that potential problems (such as serious arrhythmias or sudden cardiac death) can be prevented.
Some people with cardiomyopathy never have symptoms, and others have no symptoms in the early stages of the disease. As cardiomyopathy progresses and the heart weakens, signs and symptoms of heart failure usually appear. These signs and symptoms include:
Other signs and symptoms can include dizziness, lightheadedness, fainting during exercise, abnormal heart rhythms (arrhythmias), and an extra or unusual sound heard during the heartbeat (heart murmur).
If cardiomyopathy is suspected, the diagnosis is based on a person's:
The physical exam will identify a number of findings in patients with cardiomyopathy. The doctor will use a stethoscope to listen to the person's heart and lungs for sounds that may suggest the presence of cardiomyopathy. These sounds may even indicate a certain type of cardiomyopathy. For example, the loudness, timing, and location of a heart murmur may suggest that a person has hypertrophic obstructive cardiomyopathy. A "crackling" sound in the lungs may be a sign of heart failure, which often develops in the later stages of cardiomyopathy.
Physical signs also help the doctor diagnose cardiomyopathy. Swelling of the abdomen, legs, or feet may indicate excess fluid, which is a sign of heart failure.
Sometimes, doctors discover cardiomyopathy during a routine exam if they hear a heart murmur or if the patient has an abnormal electrocardiogram.
Doctors may order one or more tests to diagnose cardiomyopathy, including:
Because some types of cardiomyopathy run in families, the doctor may recommend looking for the disease in the parents, brothers and sisters, and children of people with cardiomyopathy.
Genetic counseling may be recommended. Genetic counseling is useful to help define and explain how the disease runs in families and to determine the chances of parents passing it on to their children.
Not everyone with cardiomyopathy needs treatment. People who have no symptoms may not need treatment. In some cases, dilated cardiomyopathy that comes on suddenly may even go away on its own. For other people with cardiomyopathy, treatment is necessary.
Specific treatments depend on the type of cardiomyopathy, how severe the symptoms and complications are, and the age and overall health of the person.
The main goals of treating cardiomyopathy are to:
Treatments for cardiomyopathy may include medicines, surgery, nonsurgical procedures, and lifestyle changes.
A number of medicines may be used to treat cardiomyopathy, including:
Doctors can use several different types of surgery to treat cardiomyopathy, including removing part of the enlarged heart muscle (septal myectomy) and implanting devices that help the heart beat more effectively. Heart transplant is sometimes used in cases of severe heart failure.
Septal myectomy. Septal myectomy (also called septal myomectomy) is open-heart surgery for people with hypertrophic obstructive cardiomyopathy and severe symptoms. It is generally used in younger patients and when medicines aren't working well.
In septal myectomy, a surgeon removes part of the thickened septum that is bulging into the left ventricle. This widens the pathway in the ventricle that leads to the aortic valve and improves blood flow through the heart and out to the body. The tissue that is removed does not grow back. If necessary, the mitral valve can be repaired or replaced at the same time. This surgery is often successful, and the person can return to a normal life with no symptoms.
Surgically implanted devices. Surgeons can place several different types of devices in the heart to help it beat more effectively. One device is a pacemaker, which electronically helps maintain normal heart rhythm. Sometimes, doctors choose to use a biventricular pacemaker, which coordinates contractions between the heart's left and right ventricles.
A left ventricular assist device (LVAD) helps the heart pump blood to the body. LVAD can be used as a long-term therapy or as a short-term treatment for people who are waiting for a heart transplant.
An implantable cardioverter defibrillator (ICD) is used in people who are at risk of life-threatening arrhythmia or sudden cardiac death. This small device is implanted in the chest and connected to the heart with wires. If the ICD senses a dangerous change in heart rhythm, it will send an electric shock to the heart to restore a normal heartbeat.
Heart transplant. In this surgery, a doctor replaces a person's diseased heart with a healthy heart from a person who has recently died. It is a last resort for people with heart failure when all other treatments have failed.
Alcohol septal ablation. In this procedure, a doctor injects ethanol (a type of alcohol) through a catheter into the small artery that supplies blood to the thickened area of heart muscle. The alcohol kills the cells and the thickened tissue shrinks to a more normal size. Blood can flow freely through the pathway in the ventricle that leads to the aortic valve, and symptoms improve.
The doctor may recommend lifestyle changes to manage a condition that is causing the cardiomyopathy. These changes may help reduce symptoms. Lifestyle changes may include:
People can make lifestyle choices to reduce the risk of conditions that may lead to cardiomyopathy, such as coronary artery disease, high blood pressure, and heart attack. Examples of lifestyle choices include:
People also can control high blood pressure, high blood cholesterol, and diabetes by:
Some types of cardiomyopathy, such as inherited forms, can't be prevented. Restrictive cardiomyopathy can't always be prevented because it occurs as the result of another disease. Sometimes, underlying diseases can be prevented or treated early enough to stop restrictive cardiomyopathy from developing.
It may be possible to prevent sudden cardiac death if doctors can identify a person at high risk of this event and treat him or her with an implantable cardioverter defibrillator.
Some people—especially those with hypertrophic cardiomyopathy—may live a healthy life with few problems or symptoms. Others may have serious symptoms and complications. Very rarely, cardiomyopathy can cause sudden death in young people.
Here are some things you can do if you have cardiomyopathy:
You may need to take antibiotics before seeing the dentist or having certain medical procedures. This is important because it can prevent an infection in your heart (endocarditis).
You should talk to your doctor if you notice new or worse symptoms, such as swelling in your legs or feet. These could be a sign that your condition is getting worse.
You also should talk with your doctor to find out how much exercise is right for you. People with hypertrophic cardiomyopathy should not exercise vigorously, but moderate exercise, such as walking, is often a good idea.
Your doctor can help you decide what kind of diet is right for you. Doctors will often recommend that people with hypertrophic cardiomyopathy drink lots of water and other fluids. Your doctor also may suggest a diet low in salt and fat.
Cardiomyopathy often runs in families. Your doctor may suggest that your parents, brothers and sisters, and children get checked every once in a while to see whether they have cardiomyopathy.
If you are diagnosed with cardiomyopathy, you should ask your doctor about any research studies available that you may be eligible to enroll in. Research studies often provide focused attention on questions about diagnosis and treatment. The researchers conducting studies are generally experts in the field, and they may assist you and your doctor, while also gaining information that could be helpful to other patients with cardiomyopathy.
National Institutes of Health (U.S. Department of Health and Human Services) www.nih.gov
The information on this Web site is provided by Cardiology Associates of Michigan for educational purposes only. It is not a substitute for professional medical care. If you have, or suspect you have, a health problem you should consult your physician immediately where they can diagnose and treat your symptoms.
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