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, or arrhythmias.
Usually, the exact cause of the muscle damage is never found.
Cardiomyopathy 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 heart
transplantation. Second, unlike many other forms of heart disease
that affect middle-aged and older persons, certain types of
cardiomopathies can, and often do, occur in the young. The
condition tends to be progressive and sometimes worsens fairly
As noted, there are various types of cardiomyopathy. These fall
into two major categories: "ischemic" and "nonischemic"
cardiomyopathy. 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.
By 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." Dilated
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, including children. In most cases, the disease
is idiopathic--a specific cause for the damage is never identified.
But some factors have been linked to the disease's occurrence. For
has a direct suppressant effect on the
heart. Dilated cardiomyopathy can be caused by chronic, excessive
consumption of alcohol, particularly in combination with dietary
Also, dilated cardiomyopathy occasionally occurs as a
factors are: various
, mostly viral, which lead to
an inflammation of the heart muscle (
(such as cobalt, once used in beers, for instance);
, used to treat a
different medical condition, also can damage the heart and produce
dilated cardiomyopathy. Such drugs include
, 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
," and it is the hallmark of dilated
cardiomyopathy. However, heart failure is often from heart disease
other than cardiomyopathy.Typical signs and symptoms of heart
- shortness of breath, sometimes severe and accompanied by a
cough (sometimes misdiagnosed as pneumonia or acute
- swelling of the legs and feet, resulting from fluid
accumulation that may also affect the lungs (congestion) and other
parts of the body
- abnormal weight gain
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
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
. 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. A
. 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 exists.
Therapy begins with the elimination of obvious risk factors, such
as alcohol consumption.
, especially salt restriction, may also be advised.
Drugs used to treat the condition include:
reduce excess fluid in the body;
, such as
angiotensin-converting 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 body;
, which helps to improve pumping action and
regulate heartbeat; and,
, which may be used in some patients to help regulate
heartbeat and to alter the work of the heart muscle. Also, patients
with irregular heartbeats may be put on any of various drugs to
control the rhythm.
In critical cases where the condition is advanced and the
patient does not sufficiently respond to other treatments, a
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
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 heart 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. Called
(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
The second most common form of heart muscle disease is
hypertrophic cardiomyopathy. Physicians sometimes call it by other
idiopathic hypertrophic subaortic stenosis
asymmetrical septal hypertrophy
(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 ventricle (the heart's main pumping
chamber), especially in the septum, 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.
Hypertrophic 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 cardiomyopathy is sudden 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 quivers. In
advanced stages of the disease, patients may have severe heart
failure and its associated symptoms, including fluid accumulation
By listening through a
, a physician may hear
the abnormal heart sounds characteristic of hypertrophic
(EKG, or ECG) may help
diagnose the condition by detecting changes in the electrical
activity of the heart as it beats.
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
, and a
Treatments for hypertrophic cardiomyopathy vary but can include
Patients with serious electrical and
blood-flow abnormalities must be less physically active.
Various drugs are used to treat the disease.
(to ease symptoms by slowing the
heart's pumping action),
calcium channel blockers
the heart and reduce the blood pressure in it),
(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.
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.
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.
Course of the disease
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 cardiac arrest is brought on by an abnormal
heartbeat. Over 10 years, the risk of sudden death can be 20
percent or more.
Restrictive 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 properly.
Restrictive cardiomyopathy typically results from another disease,
which occurs elsewhere in the body. In the United States,
restrictive cardiomyopathy is most commonly related to the
, in which abnormal protein fibers
(amyloid) accumulate in the heart's muscle;
inflammatory disease that causes the formation of small lumps in
, 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
: 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 restrictive 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
any of several imaging studies that provide pictures of the heart.
. A definite diagnosis
usually requires cardiac 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 cardiomyopathy, although diuretics may help control
fluid accumulation. In rare cases, surgery is sometimes used to try
to improve blood flow into the heart.
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 diagnosis.