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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.
Symptoms
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 or congestion.
Diagnosis
By listening through a stethoscope, a physician may hear the abnormal heart
sounds characteristic of hypertrophic cardiomyopathy The electrocardiogram (EKG,
or ECG) may help diagnose the condition by detecting changes in the electrical
activity of the heart as it beats.
Echocardiography 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,
cardiac catheterization, and a heart muscle biopsy.
Treatment
Treatments for hypertrophic cardiomyopathy vary but can include the following:
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 beta
blockers (to ease symptoms by slowing the heart's pumping action), calcium
channel blockers (to relax the heart and reduce the blood pressure in it),
antiarrhythmic medications, and diuretics (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.
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 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 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 transmitted.
Symptoms
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.
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