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Hypertrophic
Cardiomyopathy
Click here to learn
about:
What
is hypertrophic cardiomyopathy (HCM)?
Hypertrophic cardiomyopathy (HCM) is a complex type of
heart disease marked by thickening of the heart muscle, left ventricular
stiffness, mitral valve changes and cellular changes.
- Thickening of
the heart muscle (myocardium) occurs most
commonly at the septum, just below the aortic valve. The septum is the
muscular wall that separates the left and right side of the heart. Problems
occur when the septum between the heart's lower chambers or ventricles
is thickened. The thickened septum may cause a narrowing that can block
or reduce the blood flow from the left ventricle to the aorta - a condition
called "outflow tract obstruction." The ventricles must pump
much harder to overcome the narrowing or blockage. This type of hypertrophic cardiomyopathy may be called:
- Hypertrophic
obstructive cardiomyopathy (HOCM)
- Idiopathic hypertrophic
subaortic stenosis (IHSS)
- Hypertrophic
Cardiomyopathy (HCM)
Hypertrophic cardiomyopathy may also
cause thickening in other parts of the heart muscle, such as the bottom
of the heart called the apex, right ventricle, or throughout the entire
left ventricle.
- Stiffness in
the left ventricle is a sign of hypertrophic cardiomyopathy that occurs
as a result of the thickened septum. The left ventricle also is unable
to normally relax and fill with blood. The stiffness in the left ventricle
causes pressure to increase inside the heart.
- Mitral valve
changes: When
the outflow tract is narrowed, blood rushes through the passageway toward
the aortic valve (like a tight garden hose nozzle), dragging the leaflets
of the mitral valve with it. The mitral valve normally functions to
keep blood flowing in one direction from the left atrium (upper heart
chamber) to the left ventricle. However, the increased force of blood caused by hypertrophic
cardiomyopathy pulls the valve open and may cause blood to leak backward (called regurgitation)
into the left atrium.
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| Normal
Heart |
HCM |
- Cellular changes, or changes
in the cells of the heart muscle cells occur with hypertrophic cardiomyopathy. Through a microscope,
the cells appear disorganized and irregular (called "disarray")
instead of being organized and parallel. This disarray may impact the
electrical signals traveling through the heart and contribute to ventricular
arrhythmia (a type of abnormal heart rhythm).
 |
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| normal
cell pattern |
disorganized
pattern |
Who
is affected by hypertrophic cardiomyopathy?
HCM affects an estimated 600,000 to 1.5 million
Americans, or one in 500 people. It is more prevalent than multiple sclerosis,
which affects one in 700 people.
HCM is the most common cause of sudden cardiac death in people under age 30. HDCM may be best known for its role in cardiac
arrest and subsequent death in some young professional athletes.
What
causes HCM?
HCM can be:
- Inherited:
HCM
may be inherited, caused by an abnormality in the gene that codes the
characteristics for the heart muscle. When the gene defect is present,
the type of HCM that develops varies greatly within the family. In addition,
some people who have the HCM gene may never develop the disease.
- Acquired:
HCM my be acquired, the result of high blood pressure or aging.
- Unknown:
In
other instances, the cause of HCM is unknown.
Because
the cause of HCM varies, it is frequently difficult to identify a high-risk
population.
What
are the symptoms of HCM?
Many
people with HCM have no symptoms or only minor symptoms, and live a normal
life. Other people develop symptoms, which progress and worsen as the
heart function worsens. Symptoms can occur at any age and may include:
- Chest
pain or pressure that usually occurs with
exercise or physical activity, but also may occur with rest or after
meals.
- Shortness
of breath (dyspnea) and fatigue, especially
with exertion. These symptoms are more common in adults with HCM and
are most likely caused by backup of pressure in the left atrium and
to the lungs.
- Syncope
(fainting or passing out) affects about 15
to 25 percent of HCM patients. Syncope with HCM may be caused by irregular
heart rhythms, abnormal responses of the blood vessels during exercise,
or no cause may be found.
- Palpitations
(fluttering in the chest) due to abnormal
heart rhythms (arrhythmias), such as atrial fibrillation or ventricular
tachycardia. Atrial fibrillation occurs in about 25 percent of those
with HCM, and increases risk for blood clots and heart failure.
- Sudden
death occurs in a small number of patients
with HCM. See risk identification for more information.
How
is HCM diagnosed?
The diagnosis of HCM
is based on:
Medical
history:
Your doctor will ask you many questions about your symptoms and family
history.
Physical
exam: Your
doctor will listen to your heart and lungs. Patients with severe hypertrophic
obstructive cardiomyopathy (HOCM, or outflow tract obstruction) may have
a heart murmur.
Tests:
Echocardiogram is the most common test used to diagnose HCM, as the characteristic
thickening of the heart walls is usually visible on the echo. Other tests
may include blood tests, electrocardiogram, chest x-ray, echocardiogram,
exercise stress test, cardiac catheterization and magnetic resonance imaging
(MRI). Click
here to learn more about these diagnostic tests and procedures
How
is hypertrophic cardiomyopathy treated?
The type of
treatment prescribed depends on:
- Whether there is
narrowing in the out-flow tract (the path blood travels to leave the
heart)
- How the heart is
functioning
- Patient's symptoms
- The age and activity
level of the patient
- The presence of
arrhythmias
Treatment is aimed
at preventing symptoms and complications and includes risk identification
and regular follow-up, lifestyle changes, medications and procedures as
needed.
Risk
Identification
It is important to
identify the small number of patients with HCM who are at higher risk
for sudden cardiac
death, so preventive measures can be taken. People with HCM who have
a higher risk for sudden death include:
- Those who have
family members who had sudden cardiac death
- Young patients
with several episodes of syncope (fainting)
- Those who have
an abnormal blood pressure response with exercise
- Adults who have
a history of arrhythmia with fast heart rate
- Those with severe
symptoms and poor heart function
If you have two or
more risk factors for sudden death, your doctor may prescribe preventive
treatments such as antiarrhythmic medications or an implantable
cardioverter defibrillator (ICD). Most people with HCM have a low
risk for sudden cardiac death. Talk to your doctor about any personal
concerns.
Medications
Often, medications
are used to treat symptoms and prevent further complications. Medications
help relax the heart and reduce the degree of obstruction so the heart
can pump more efficiently. Beta-blockers and calcium channel blockers
are two classes of medications that may be prescribed. If you have an
arrhythmia, your doctor may prescribe medications to control your heart
rate or decrease the occurrence of arrhythmias. Your doctor will discuss
which medications are best for you.
 Check
the drug
search
to find out more about your medications.
It is important to
know:
- the names
of your medications
- what they
are for
- how often
and at what times to take them
You may be told to
avoid certain medications, such as nitrates because they lower blood pressure,
or digoxin, because it increases the force of the heart’s contraction.
Antibiotic medications
are prescribed to prevent bacterial endocarditis, a potentially life-threatening
condition.
Procedures:
septal myectomy, ethanol ablation, pacemaker, ICD
 Septal
myectomy
During this surgical procedure, the surgeon removes a small amount
of the thickened septal wall to widen the outflow tract (the path the
blood takes) from the left ventricle to the aorta. Myectomy is considered
when medications are not effective in treating HCM. This frequently eliminates
the mitral valve regurgitation. This procedure has a high percentage of
positive results. Click here to see animation 
Ethanol ablation
This procedure, also called septal ablation, is performed in the cardiac
catheterization laboratory. First, the small coronary artery that supplies
blood flow to the septum is located during a cardiac catheterization procedure.
A balloon catheter is inserted into the artery and inflated. A contrast
agent is injected to locate the thickened septal wall that narrows the
passageway from the left ventricle to the aorta. When the bulge is located,
a tiny amount of pure alcohol is injected through the catheter. The alcohol
kills the cells on contact, causing the septum to shrink back to a more
normal size over the following months, widening the passage for blood
flow. Click here to see animation
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| before
ablation - thick septum, narrowed outflow tract |
balloon
and tube inside septal perforator (blood vessel) in swollen septum
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after
ablation - normal outflow |
Implantable
Cardioverter Defibrillators (ICD)
ICDs are suggested for patients at risk for
life-threatening arrhythmias or sudden cardiac death. The ICD is a small
device placed just under the skin and is connected to wire leads that
are threaded through the vein to the heart. An ICD constantly monitors
the heart rhythm. When it detects a very fast, abnormal heart rhythm,
it delivers energy to the heart muscle to cause the heart to beat in a
normal rhythm again.
For patients with
non-obstructive HCM
Non-obstructive HCM symptoms may be treated with medications. If heart
failure occurs, treatment is aimed at controlling it. (Click
here to learn more about heart failure)
Lifestyle
changes:
Diet:
Drinking at least
six to eight, 8-ounce glasses of water a day is important, unless fluids
are restricted. In hot weather, you should increase your fluid intake.
Fluid and sodium restrictions
may be necessary for some patients if heart failure symptoms are present.
Ask your physicians about specific fluid and dietary guidelines, including
information about alcoholic beverages and caffeinated products.
Exercise:
Your doctor will tell
you if you may exercise or not. Most patients with HCM are able to do
noncompetitive aerobic exercise. Heavy weight lifting is not recommended.
Regular follow-up
Visits:
Patients with HCM
should have an annual follow-up visit with their cardiologist to monitor
their condition, unless more frequent appointments are needed. Follow-up
appointments may be more frequent when HCM is first diagnosed.
| What
is endocarditis?
Endocarditis
occurs when germs (especially bacteria) enter your blood stream
and attack the lining of your heart valves, causing growths on
the valve, holes in the valve or scarring of the valve tissue,
most often resulting in leaky heart valves. |
Prevention
of Infection:
People with HCM may
have an increased risk for developing infective endocarditis. Those at
risk should follow these precautions:
- Tell all your doctors
and dentist you have HCM. They should prescribe antibiotics to prevent
an infection before performing any procedure that may cause bleeding
(dental, respiratory, and gastrointestinal (GI) procedures). Ask your
doctor about antibiotic guidelines.
- Call your doctor
if you have symptoms of an infection, such as temperature of more than
101 degrees Fahrenheit or 38.4 degrees Celsius.
- Take good care
of your teeth and gums.
- Ask your doctor
if you need to take endocarditis preventions. For specific guidelines,
see Infective
Endocarditis and Heart Disease.
For information
and support
The Hypertrophic
Cardiomyopathy Association (HCMA): The Hypertrophic Cardiomyopathy
Association (HCMA) is dedicated to support and educate those with HCM,
their families and other health care professionals. They may be contacted
at P.O. Box 306, Hibernia, NJ 07842; phone 973/983-7429; email at support@4hcm.org;
or the website at http://www.4hcm.org.*
 Hypertrophic
Cardiomyopathy: For Patients, Their Families and Interested Physicians
- a very helpful guide for those with hypertrophic cardiomyopathy. Books
can be ordered at http://www.4hcm.org*
or by sending payment to the HCMA, P.O. Box 306, Hibernia, NJ 07842. Books
cost $26.95 plus $3.00 shipping and handlingor are free with the first year's membership
of $50.00 to the HCMA.
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