Cardiomyopathy is a disease of the heart muscle. The heart loses its ability to pump blood and, in some instances, heart rhythm is disturbed, leading to irregular heartbeats,
Usually, the exact cause of the muscle damage is never found.
differs from many other heart disorders in a couple of ways. First, the types
not related to coronary atherosclerosis are fairly uncommon. Cardiomyopathy
affects about 50,000 Americans. However, the condition is a leading reason for
Second, unlike many other forms of heart disease that affect middle-aged and
older persons, certain types of
can, and often do, occur in the young. The condition tends to be progressive and
sometimes worsens fairly quickly.
Nonischemic CardiomyopathyAs noted, there are various types of
cardiomyopathy. These fall into two major categories: "ischemic" and
- Ischemic cardiomyopathy typically refers to heart muscle damage that
results from coronary artery disease, such as heart attack, and will not be
discussed here (see page 8 on how to get information on the disorder).
- Nonischemic cardiomyopathy includes several types. The three main types
are covered in this fact sheet. They are: dilated, hypertrophic, and
restrictive. The name of each describes the nature of its muscle damage.
Dilated (Congestive) CardiomyopathyBy far the most common type of
nonischemic cardiomyopathy, the dilated (stretched) form occurs when
disease-affected muscle fibers lead to enlargement, or dilation, of one or more
chambers of the heart. This weakens the heart's pumping ability. The heart tries
to cope with the pumping limitation by further enlarging and stretching--a
process known as "compensation."
cardiomyopathy occurs most often in middle-aged people and more often in men
than women. However, the disease has been diagnosed in people of all ages,
In most cases, the disease is
specific cause for the damage is never identified.
But some factors have been linked to the disease's occurrence. For
instance, alcohol has a direct suppressant effect on the heart. Dilated
cardiomyopathy can be caused by chronic, excessive consumption of alcohol,
particularly in combination with dietary deficiencies. Also, dilated
cardiomyopathy occasionally occurs as a complication of pregnancy and
childbirth. Other factors are: various infections, mostly viral, which lead to
an inflammation of the heart muscle (myocarditis); toxins (such as cobalt, once
used in beers, for instance); and, rarely, heredity.
Some drugs, used to treat a different medical condition, also can damage the
heart and produce dilated cardiomyopathy. Such drugs include doxorubicin and
daunorubicin, both used to treat cancer.
Whatever the cause, the clinical and pathological manifestations of dilated
cardiomyopathy are usually the same.
Dilated cardiomyopathy can be present for several years without causing
significant symptoms. With time, however, the enlarged heart gradually weakens.
This condition is commonly called "
failure," and it is the hallmark of dilated cardiomyopathy. Typical signs
and symptoms of heart failure include: fatigue; weakness; shortness of breath,
sometimes severe and accompanied by a cough, particularly with exertion or when
lying down; and swelling of the legs and feet, resulting from fluid accumulation
that may also affect the lungs
(congestion) and other parts of the body. It also produces abnormal weight
gain. (The cough and congestion mimic and, therefore, can be misdiagnosed as
pneumonia or acute bronchitis. Also,
failure is often from heart disease other than cardiomyopathy.)
Because of the congestion, some physicians use the older term "congestive
cardiomyopathy" to refer to dilated cardiomyopathy. In advanced stages of the
disease, the congestion may cause pain in the chest or abdomen.
In advanced stages, some patients develop irregular heartbeats, which can be
serious and even life threatening.
Once symptoms appear, the condition may be tentatively diagnosed based on a
physical examination and a patient's medical history. More often, though,
further examination is needed to differentiate dilated cardiomyopathy from other
causes of heart failure.
A firm diagnosis typically requires a chest x ray to show whether the heart
is enlarged, an
to reveal any abnormal electrical activity of the heart, and an
which uses sound waves to produce pictures of the heart.
Other, more specific tests may also be needed. These include:
- A radionuclide ventriculogram. This involves injecting low-dose
radioactive material (usually equal to that in a set of chest x rays) into a
vein, through which it flows to the heart. Pictures are generated by a special
camera to show how well the heart is functioning.
catheterization. In this procedure, a thin plastic tube is inserted
through a blood vessel until it reaches the heart. A dye is injected and x
rays taken to assess the heart's structure and function.
Since dilated cardiomyopathy is hard to diagnose early, it is rarely treated
in its beginning stage.
The goal of treatment is to relieve any complicating factor, if known,
control the symptoms, and stop the disease's progression. However, no cure now
Therapy begins with the elimination of obvious risk factors, such as alcohol
consumption. Weight loss and dietary changes, especially salt restriction, may
also be advised.
Drugs used to treat the condition include:
Also, patients with
irregular heartbeats may be put on any of various drugs to control the rhythm.
which reduce excess fluid in the body;
- Vasodilators, such as
enzyme (ACE) inhibitors, which relax blood vessels, helping to lower blood
pressure and reducing the effort needed by the heart to pump blood through the
which helps to improve pumping action and regulate heartbeat; and,
blockers, which may be used in some patients to help regulate heartbeat
and to alter the work of the heart muscle.
In critical cases where the condition is advanced and the patient does not
sufficiently respond to other treatments, a heart transplantation may be needed.
The patient's heart is replaced with a donor heart. Most heart transplant
recipients are under age 60 and in good health other than their diseased heart.
Course of the disease
As the heart enlarges, it steadily decreases its efficiency in pumping blood
and the amount of blood it can pump. As a result, some patients cannot perform
even simple physical activities.
However, the disease also may remain fairly stable for years, especially with
treatment and regular evaluation by a physician.
Unfortunately, by the time it is diagnosed, the disease often has reached an
advanced stage and
failure has occurred. Consequently, about 50 percent of patients with
dilated cardiomyopathy live 5 years once heart failure is diagnosed; about 25
percent live 10 years after such a diagnosis.
Typically, patients die from a continued decline in heart muscle strength,
but some die suddenly of irregular heartbeats.
For patients with advanced disease, heart transplantation greatly improves
survival: 75 percent of patients live 5 years after a transplantation. However,
in the United States, the scarcity of donor hearts limits the number of
transplantations to about 2,000 persons a year. Those who qualify for heart
transplantation often have to wait months, or even years, for a suitable donor
heart. Some patients with dilated cardiomyopathy die awaiting a transplant but,
according to recent studies, others improve enough from aggressive medical
treatment to be taken off the waiting list.
Also, some critically ill cardiomyopathy patients with declining heart
function use a small, implanted mechanical pump as a bridge to transplantation.
ventricular assist devices (LVADs), these pumps take over part or virtually
all of the heart's blood pumping activity. The devices provided only temporary
assistance and are not now used as substitutes for heart transplantation.
Hypertrophic CardiomyopathyThe second most common form of heart
muscle disease is
cardiomyopathy. Physicians sometimes call it by other names: idiopathic
hypertrophic subaortic stenosis (IHSS), asymmetrical septal hypertrophy (ASH),
or hypertrophic obstructive cardiomyopathy (HOCM).
In hypertrophic cardiomyopathy, the growth and arrangement of muscle fibers
are abnormal, leading to thickened heart walls. The greatest thickening tends to
occur in the left
(the heart's main pumping chamber), especially in the
the wall that separates the left and right ventricles. The thickening reduces
the size of the pumping chamber and obstructs blood flow. It also prevents the
heart from properly relaxing between beats and so filling with blood.
Eventually, this limits the pumping action.
cardiomyopathy is a rare disease, occurring in no more than 0.2 percent of
the U.S. population. It can affect men and women of all ages. Symptoms can
appear in childhood or adulthood.
Most cases of hypertrophic cardiomyopathy are inherited. Because of this, a
patient's family members often are checked for signs of the disease, although
the signs may be much less evident or even absent in them. In other cases, there
is no clear cause.
Many patients have no symptoms. For those who do, the most common are
breathlessness and chest discomfort. Other signs are fainting during physical
activity, strong rapid heartbeats that feel like a pounding in the chest, and
fatigue, especially with physical exertion.
In some cases, the first and only manifestation of hypertrophic
death, caused by a chaotic heartbeat. The heart's lower chambers beat so
chaotically and fast that no blood is pumped. Instead of beating, the heart
In advanced stages of the disease, patients may have severe
failure and its associated symptoms, including fluid accumulation or
By listening through a stethoscope, a physician may hear the abnormal heart
sounds characteristic of
(EKG, or ECG) may help diagnose the condition by detecting changes in the
electrical activity of the heart as it beats.
is one of the best tools for diagnosing hypertrophic cardiomyopathy. It uses
sound waves to detect the extent of muscle-wall thickening and to assess the
status of the heart's functioning.
Physicians also may request radionuclide studies to gather added information
about the disease's effect on how the heart is pumping blood.
Other tests that also may provide useful information are the chest x ray,
catheterization, and a heart muscle biopsy.
Treatments for hypertrophic cardiomyopathy vary but can include the
Course of the disease
- Lifestyle changes. Patients with serious electrical and blood-flow
abnormalities must be less physically active.
- Medications. Various drugs are used to treat the disease. They include
blockers (to ease symptoms by slowing the heart's pumping action),
channel blockers (to relax the heart and reduce the blood pressure in it),
antiarrhythmic medications, and
(to ease heart failure symptoms).
However, drugs do not work in all cases or may cause adverse side effects,
such as fluid in the lungs, very low blood pressure, and sudden death. Then,
other treatment, such as a pacemaker or surgery, may be needed.
- Pacemakers. These change the pattern and decrease the force of the heart's
contractions. The pacemaker can reduce the degree of obstruction and so
relieve symptoms. A pacemaker needs to be carefully monitored after its
insertion in order to properly adjust the electrical impulse. Some patients
who have a pacemaker inserted feel no relief and go on to have heart surgery.
- Surgery. This usually calls for removal of part of the thickened septum
(the muscle wall separating the chambers) that is blocking the blood flow.
Sometimes, surgery also must replace a heart valve--the mitral valve, which
connects the left ventricle and the left atrium, the upper chamber that
receives oxygen-rich blood from the lungs.
Surgery to remove the thickening eases symptoms in about 70 percent of
patients but results in death in about 1 to 3 percent of patients. Also, about
5 percent of those who have surgery develop a slow heartbeat, which is then
corrected with a pacemaker.
The course of the disease varies. Many patients remain stable; some improve;
some worsen in symptoms and lead severely restricted lives. Patients may need
drug treatment and careful medical supervision for the rest of their lives.
Hypertrophic cardiomyopathy patients also are at risk of sudden death. About
2 to 3 percent die each year because the heart suddenly stops beating. This
arrest is brought on by an abnormal heartbeat. Over 10 years, the risk of
sudden death can be 20 percent or more.
cardiomyopathy is rare in the United States and most other industrial
nations. In this disease, the walls of the ventricles stiffen and lose their
flexibility due to infiltration by abnormal tissue. As a result, the heart
cannot fill adequately with blood and eventually loses its ability to pump
cardiomyopathy typically results from another disease, which occurs
elsewhere in the body. In the United States, restrictive cardiomyopathy is most
commonly related to the following: amyloidosis, in which abnormal protein fibers
(amyloid) accumulate in the heart's muscle; sarcoidosis, an inflammatory disease
that causes the formation of small lumps in organs; and hemochromatosis, an iron
overload of the body, usually due to a genetic disease.
In general, restrictive cardiomyopathy does not appear to be inherited;
however, some of the diseases that lead to the condition are genetically
Typical signs of the condition include symptoms of congestive heart failure:
weakness, fatigue, and breathlessness. Swelling of the legs, caused by fluid
retention, occurs in a significant number of patients. Other symptoms include
nausea, bloating, and poor appetite, probably because of the retention of fluid
around the liver, stomach, and intestines.
A physician may suspect
cardiomyopathy based on a patient's symptoms and the presence of another
disease. Although symptoms of congestive heart failure may predominate, the size
of the heart remains relatively small, unlike other cardiomyopathies.
Diagnostic information comes from an electrocardiogram or any of several
imaging studies that provide pictures of the heart. These include
echocardiography, magnetic resonance imaging, and computed tomography.
A definite diagnosis usually requires
catheterization studies or a biopsy, in which a tiny piece of
tissue--including heart muscle--is removed for laboratory analysis.
Restrictive cardiomyopathy has no specific treatment. The underlying disease
that leads to the heart problem also may not be treatable.
In general, the use of traditional heart drugs has been limited in this
may help control fluid accumulation.
In rare cases, surgery is sometimes used to try to improve blood flow into
Course of the disease
The condition is similar to dilated cardiomyopathy and tends to worsen with
time. Only about 30 percent of patients survive more than 5 years after
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