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IAC (SM) Newsletter Database (TM)
Copyright 2003 Copyright by President and Fellows of Harvard
College. All Rights Reserved
Harvard Heart Letter
February 1, 2003
SECTION: No. 6, Vol. 13; Pg. 0 ; ISSN: 1051-5313
IAC-ACC-NO: 96292374
LENGTH: 1629 words
HEADLINE: When big-hearted is bad.
AUTHOR-ABSTRACT:
THIS IS THE FULL TEXT: COPYRIGHT 2003 President and Fellows of Harvard College
on behalf of Harvard Health Publications (Harvard)/Staywell. Inc. Subscription:
$ 32.00 per year. Published monthly. Consumer Health Publishing Group for
Harvard Health Publications, One Atlantic Street, Suite 604, Stamford, CT 06091.
FAX 617-432-1506.
BODY:
An overgrown heart muscle can kill. In most cases, though, it's just a
reason for extra care.
A strong, muscular heart is a foundation of good health - except when it's
too muscular. That's the case with hypertrophic cardiomyopathy
(high-per-TROE-fik car-dee-oh-my-AH-puh-thee), an inherited condition in which
part of the heart looks like it's pumped up on steroids. Instead of helping the
heart work more efficiently, the extra muscle can interfere with its function.
Hypertrophic cardiomyopathy, or HCM, is a confusing condition. Over the
years it has been called at least 75 different names. And because many of the
early reports about it were penned by researchers at high-level cardiac centers,
which tend to receive the sickest patients, it got a reputation as a disabling
and deadly disease.
There's no question that HCM can restrict life, or even cut it short. The
latest research, though, emphasizes that the risks of this condition have been
overstated. Some people never know they have it. For many others, it's a
controllable condition that may have little impact on life and longevity.
As heart diseases go, HCM isn't as common as coronary artery disease or
congestive heart failure. It affects only about 1 in every 500 U.S. adults.
Still, that's enough people to fill a city the size of Miami or Minneapolis.
Cause and effect
HCM stems from a mutation in any one of at least 10 genes that code for
proteins in heart muscle fibers. These abnormal genes make heart muscle fibers
grow in a disorganized fashion.
They also somehow force extra muscle growth, especially in the left
ventricle (the muscular lower chamber that pumps blood to the body) and the
septum (the wall separating the left and right sides of the heart). In a normal
heart, the septum is 10-12 millimeters thick. That's just under half an inch. In
HCM, it can measure as much as 60 millimeters, or 2.4 inches thick.
This extra muscle poses several problems:
* It crowds the space inside the left ventricle, taking up room normally
used to collect oxygenated blood. The extra muscle is also stiff and has trouble
relaxing between beats. If the left ventricle can't fill properly, it may not be
able to deliver enough blood to meet the body's needs, especially during
physical activity. In severe cases, fluid can back up into the lungs.
* It can throw the mitral valve out of alignment. Instead of closing tightly
after a contraction squeezes blood from the left atrium to the left ventricle,
the mitral valve may flap open and block blood that's being pumped from the left
ventricle to the aorta (and so to the body). This can cause dizziness, fainting,
or breathlessness. It can also make exercise difficult.
* It may demand more oxygen than the body can supply. If arteries feeding
the left ventricle and septum can't reach all parts of the thickened muscle, or
can't deliver enough oxygen to them, chest pain can follow. This is much like
the pain from angina caused by cholesterol-clogged arteries.
* It can cause disturbed and sometimes deadly heart rhythms. Disorganized
muscle fibers and scar tissue from stretched heart muscle can interfere with the
pattern of electrical signals that governs regular heartbeats.
Detecting HCM
In youngsters and young athletes, the first sign of HCM is sometimes sudden
death caused by a lethal heart rhythm. Most people with HCM, though, find out in
less dramatic ways. Some experience symptoms such as fainting spells,
breathlessness, chest pain, or palpitations that are traced to a hypertrophic
heart. Others learn they have it when they see a doctor because a close relative
has been diagnosed with this condition. (See A family affair.)
Checking for HCM is relatively straightforward. A heart murmur heard through
a stethoscope can indicate that the mitral valve is opening in the strong,
turbulent outflow from a narrowed left ventricle. An electrocardiogram can
reveal abnormalities that signal thickened heart muscle. The ultimate test is an
echocardiogram. Using sound waves, this test can show the size and shape of the
heart as well as the blood-flow pattern inside it.
A family affair
HCM occasionally crops up in people who don't have relatives with it. Most
of the time it's inherited. If you have HCM, each of your children has a 50/50
chance of inheriting a faulty gene. Because of this pattern, when an individual
is diagnosed with HCM, it's a good idea for his or her family members - brothers
and sisters and their children - to be checked for the disease.
Managing HCM
This condition can make itself known at any stage of life, from infancy to
old age. Symptoms can stay stable for years, then flare and subside. Or the
condition can appear suddenly and quickly worsen. This variability makes HCM
unique among cardiovascular diseases.
It also means there's no one-size-fits-all therapy. Treatment is based on
the presence and severity of symptoms or complications. If you have neither,
then you need vigilance (see Living with HCM) but not treatment. Mild symptoms
often respond to drug therapy. When they don't, or if they interfere with daily
life, a procedure to shrink the overdeveloped heart tissue may be in order.
Ongoing or potential rhythm problems must also be treated.
Drug therapy. Drugs are the first line of defense against shortness of
breath, chest pain, and other symptoms of HCM. Beta blockers reduce the heart's
workload and help the ventricles fill with blood. So do calcium channel
blockers. A drug called disopyramide (Norpace) can help the heart relax and
prevent erratic heart rhythms such as atrial fibrillation. Amiodarone
(Cordarone) is another drug used to control erratic rhythms. If HCM leads to
atrial fibrillation, a blood thinner such as warfarin can help ward off the
strokes that this erratic rhythm can generate.
Surgery. If drug therapy can't relieve HCM symptoms, the next step could be
an operation to remove some muscle from the septum. This procedure is relatively
safe (98 of 100 people survive it) and effective (it eases symptoms in 70 of 100
people). But because it requires open-heart surgery and the use of a heart-lung
bypass machine, recovery can take weeks, and complications can arise.
Alcohol ablation. A new technique offers an alternative to surgery. It uses
an alcohol injection to thin the upper part of the septum. Alcohol ablation
eases symptoms as much as surgery does, but with fewer complications, a shorter
hospital stay, and a faster recovery. Although the early results look good,
doctors don't yet know the long-term effects of this procedure. One worry is
that the scar left behind by the alcohol injection could lead to dangerous
rhythm problems later in life. The National Heart, Lung, and Blood Institute is
now recruiting participants for a study on this technique.
The HCMA does not support the protocol currently in use by the NIH for this research
Implantable pacemaker. When HCM blocks or reroutes electrical signals to the
ventricles, an implanted pacemaker may be needed.
Implantable cardioverter/defibrillator (ICD). The sudden and unpredictable
onset of fast, erratic contractions of the ventricles is a common cause of death
among people with HCM. The only treatment is to abort these lethal arrhythmias -
called ventricular tachycardia and ventricular fibrillation - with an electric
shock. This can be done with an implantable cardioverter/defibrillator. An ICD
constantly monitors the heart's rhythm and delivers a shock if it senses
trouble.
Living with HCM
Because hypertrophic cardiomyopathy affects different people in different
ways, everyone needs a different strategy for adapting to life with this
condition. Here are a few general guides:
* Call your doctor right away if you faint, feel dizzy, or find yourself
unexpectedly short of breath. These could be signs of potentially dangerous
HCM-associated trouble.
* For most people with HCM, light to moderate exercise is perfectly fine,
even healthy. Activity that causes or increases symptoms, though, must be
treated with caution and advice from a doctor. Most experts recommend that
people with HCM not participate in competitive sports, physically demanding
activities, or activities that strain the heart, such as weight lifting.
* Drink plenty of fluids, especially when you exercise. Dehydration worsens
the left ventricle's filling problems.
* Follow a basic heart-healthy eating plan. Beyond that, you don't need a
special diet or vitamin supplements.
* If your blood pressure is high, work with your doctor to get it under
control. High blood pressure can further enlarge the left ventricle, the last
thing someone with HCM needs.
* Ask your doctor about taking antibiotics before dental work and other
invasive procedures (Harvard Heart Letter, September 2002). A hypertrophic heart
is susceptible to an infection of the heart valves that can originate with such
procedures.
* Be scrupulous about getting regular checkups. If you are doing well and
have no symptoms, once a year should be fine. But if you have symptoms or have
an ICD, you'll need to see your doctor more often.
* Help the cause by taking part in a clinical trial. There's still a lot to
be learned about HCM, from the genes that cause it to the treatments that
control it. If you have the time or interest, ask your doctor about trials for
which you might be eligible.
For more information
Hypertrophic Cardiomyopathy by Barry Maron, MD, with Lisa Salberg. Futura
Publishing Co., Armonk, NY, 2001.
The Hypertrophic Cardiomyopathy Association, 973-983-7429 or
www.hcma-heart.com or www.4hcm.org
Or visit www.health.harvard.edu/heart
IAC-CREATE-DATE: January 9, 2003
LOAD-DATE: January 11, 2003
IAC (SM) Newsletter Database (TM)
Copyright 2003 Copyright by President and Fellows of Harvard
College. All Rights Reserved
Harvard Heart Letter
February 1, 2003
SECTION: No. 6, Vol. 13; Pg. 0 ; ISSN: 1051-5313
IAC-ACC-NO: 96292374
LENGTH: 1629 words
HEADLINE: When big-hearted is bad.
AUTHOR-ABSTRACT:
THIS IS THE FULL TEXT: COPYRIGHT 2003 President and Fellows of Harvard College
on behalf of Harvard Health Publications (Harvard)/Staywell. Inc. Subscription:
$ 32.00 per year. Published monthly. Consumer Health Publishing Group for
Harvard Health Publications, One Atlantic Street, Suite 604, Stamford, CT 06091.
FAX 617-432-1506.
BODY:
An overgrown heart muscle can kill. In most cases, though, it's just a
reason for extra care.
A strong, muscular heart is a foundation of good health - except when it's
too muscular. That's the case with hypertrophic cardiomyopathy
(high-per-TROE-fik car-dee-oh-my-AH-puh-thee), an inherited condition in which
part of the heart looks like it's pumped up on steroids. Instead of helping the
heart work more efficiently, the extra muscle can interfere with its function.
Hypertrophic cardiomyopathy, or HCM, is a confusing condition. Over the
years it has been called at least 75 different names. And because many of the
early reports about it were penned by researchers at high-level cardiac centers,
which tend to receive the sickest patients, it got a reputation as a disabling
and deadly disease.
There's no question that HCM can restrict life, or even cut it short. The
latest research, though, emphasizes that the risks of this condition have been
overstated. Some people never know they have it. For many others, it's a
controllable condition that may have little impact on life and longevity.
As heart diseases go, HCM isn't as common as coronary artery disease or
congestive heart failure. It affects only about 1 in every 500 U.S. adults.
Still, that's enough people to fill a city the size of Miami or Minneapolis.
Cause and effect
HCM stems from a mutation in any one of at least 10 genes that code for
proteins in heart muscle fibers. These abnormal genes make heart muscle fibers
grow in a disorganized fashion.
They also somehow force extra muscle growth, especially in the left
ventricle (the muscular lower chamber that pumps blood to the body) and the
septum (the wall separating the left and right sides of the heart). In a normal
heart, the septum is 10-12 millimeters thick. That's just under half an inch. In
HCM, it can measure as much as 60 millimeters, or 2.4 inches thick.
This extra muscle poses several problems:
* It crowds the space inside the left ventricle, taking up room normally
used to collect oxygenated blood. The extra muscle is also stiff and has trouble
relaxing between beats. If the left ventricle can't fill properly, it may not be
able to deliver enough blood to meet the body's needs, especially during
physical activity. In severe cases, fluid can back up into the lungs.
* It can throw the mitral valve out of alignment. Instead of closing tightly
after a contraction squeezes blood from the left atrium to the left ventricle,
the mitral valve may flap open and block blood that's being pumped from the left
ventricle to the aorta (and so to the body). This can cause dizziness, fainting,
or breathlessness. It can also make exercise difficult.
* It may demand more oxygen than the body can supply. If arteries feeding
the left ventricle and septum can't reach all parts of the thickened muscle, or
can't deliver enough oxygen to them, chest pain can follow. This is much like
the pain from angina caused by cholesterol-clogged arteries.
* It can cause disturbed and sometimes deadly heart rhythms. Disorganized
muscle fibers and scar tissue from stretched heart muscle can interfere with the
pattern of electrical signals that governs regular heartbeats.
Detecting HCM
In youngsters and young athletes, the first sign of HCM is sometimes sudden
death caused by a lethal heart rhythm. Most people with HCM, though, find out in
less dramatic ways. Some experience symptoms such as fainting spells,
breathlessness, chest pain, or palpitations that are traced to a hypertrophic
heart. Others learn they have it when they see a doctor because a close relative
has been diagnosed with this condition. (See A family affair.)
Checking for HCM is relatively straightforward. A heart murmur heard through
a stethoscope can indicate that the mitral valve is opening in the strong,
turbulent outflow from a narrowed left ventricle. An electrocardiogram can
reveal abnormalities that signal thickened heart muscle. The ultimate test is an
echocardiogram. Using sound waves, this test can show the size and shape of the
heart as well as the blood-flow pattern inside it.
A family affair
HCM occasionally crops up in people who don't have relatives with it. Most
of the time it's inherited. If you have HCM, each of your children has a 50/50
chance of inheriting a faulty gene. Because of this pattern, when an individual
is diagnosed with HCM, it's a good idea for his or her family members - brothers
and sisters and their children - to be checked for the disease.
Managing HCM
This condition can make itself known at any stage of life, from infancy to
old age. Symptoms can stay stable for years, then flare and subside. Or the
condition can appear suddenly and quickly worsen. This variability makes HCM
unique among cardiovascular diseases.
It also means there's no one-size-fits-all therapy. Treatment is based on
the presence and severity of symptoms or complications. If you have neither,
then you need vigilance (see Living with HCM) but not treatment. Mild symptoms
often respond to drug therapy. When they don't, or if they interfere with daily
life, a procedure to shrink the overdeveloped heart tissue may be in order.
Ongoing or potential rhythm problems must also be treated.
Drug therapy. Drugs are the first line of defense against shortness of
breath, chest pain, and other symptoms of HCM. Beta blockers reduce the heart's
workload and help the ventricles fill with blood. So do calcium channel
blockers. A drug called disopyramide (Norpace) can help the heart relax and
prevent erratic heart rhythms such as atrial fibrillation. Amiodarone
(Cordarone) is another drug used to control erratic rhythms. If HCM leads to
atrial fibrillation, a blood thinner such as warfarin can help ward off the
strokes that this erratic rhythm can generate.
Surgery. If drug therapy can't relieve HCM symptoms, the next step could be
an operation to remove some muscle from the septum. This procedure is relatively
safe (98 of 100 people survive it) and effective (it eases symptoms in 70 of 100
people). But because it requires open-heart surgery and the use of a heart-lung
bypass machine, recovery can take weeks, and complications can arise.
Alcohol ablation. A new technique offers an alternative to surgery. It uses
an alcohol injection to thin the upper part of the septum. Alcohol ablation
eases symptoms as much as surgery does, but with fewer complications, a shorter
hospital stay, and a faster recovery. Although the early results look good,
doctors don't yet know the long-term effects of this procedure. One worry is
that the scar left behind by the alcohol injection could lead to dangerous
rhythm problems later in life. The National Heart, Lung, and Blood Institute is
now recruiting participants for a study on this technique.
The HCMA does not support the protocol currently in use by the NIH for this research
ventricles, an implanted pacemaker may be needed.
Implantable cardioverter/defibrillator (ICD). The sudden and unpredictable
onset of fast, erratic contractions of the ventricles is a common cause of death
among people with HCM. The only treatment is to abort these lethal arrhythmias -
called ventricular tachycardia and ventricular fibrillation - with an electric
shock. This can be done with an implantable cardioverter/defibrillator. An ICD
constantly monitors the heart's rhythm and delivers a shock if it senses
trouble.
Living with HCM
Because hypertrophic cardiomyopathy affects different people in different
ways, everyone needs a different strategy for adapting to life with this
condition. Here are a few general guides:
* Call your doctor right away if you faint, feel dizzy, or find yourself
unexpectedly short of breath. These could be signs of potentially dangerous
HCM-associated trouble.
* For most people with HCM, light to moderate exercise is perfectly fine,
even healthy. Activity that causes or increases symptoms, though, must be
treated with caution and advice from a doctor. Most experts recommend that
people with HCM not participate in competitive sports, physically demanding
activities, or activities that strain the heart, such as weight lifting.
* Drink plenty of fluids, especially when you exercise. Dehydration worsens
the left ventricle's filling problems.
* Follow a basic heart-healthy eating plan. Beyond that, you don't need a
special diet or vitamin supplements.
* If your blood pressure is high, work with your doctor to get it under
control. High blood pressure can further enlarge the left ventricle, the last
thing someone with HCM needs.
* Ask your doctor about taking antibiotics before dental work and other
invasive procedures (Harvard Heart Letter, September 2002). A hypertrophic heart
is susceptible to an infection of the heart valves that can originate with such
procedures.
* Be scrupulous about getting regular checkups. If you are doing well and
have no symptoms, once a year should be fine. But if you have symptoms or have
an ICD, you'll need to see your doctor more often.
* Help the cause by taking part in a clinical trial. There's still a lot to
be learned about HCM, from the genes that cause it to the treatments that
control it. If you have the time or interest, ask your doctor about trials for
which you might be eligible.
For more information
Hypertrophic Cardiomyopathy by Barry Maron, MD, with Lisa Salberg. Futura
Publishing Co., Armonk, NY, 2001.
The Hypertrophic Cardiomyopathy Association, 973-983-7429 or
www.hcma-heart.com or www.4hcm.org
Or visit www.health.harvard.edu/heart
IAC-CREATE-DATE: January 9, 2003
LOAD-DATE: January 11, 2003
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