Hypertrophic cardiomyopathy (HCM) is a disease in which the heart muscle (myocardium) becomes abnormally thick — or hypertrophied. This thickened heart muscle can make it harder for the heart to pump blood. Hypertrophic cardiomyopathy may also affect the heart's electrical system.
Hypertrophic cardiomyopathy often goes undiagnosed, because many of those with hypertrophic cardiomyopathy have few, if any, symptoms. In a small number of people with this condition, the thickened heart muscle can cause signs and symptoms, such as shortness of breath and problems in the heart's electrical system resulting in life-threatening abnormal heart rhythms (arrhythmias).
Fortunately, people with hypertrophic cardiomyopathy often lead normal lives with no significant problems.
Illustrations of a normal heart (left) and a heart with hypertrophic cardiomyopathy (HCM). Note that the heart walls (muscle) are much thicker (hypertrophied) in the HCM heart. ...
Hypertrophic cardiomyopathy symptoms include:
Hypertrophic cardiomyopathy is usually caused by gene mutations. It's thought these mutations cause the heart muscle to grow abnormally thick. People with hypertrophic cardiomyopathy also have an abnormal arrangement of heart muscle fibers. The heart muscle cells become jumbled, known as myofiber disarray. This disarray can contribute to an irregular heartbeat (arrhythmia) in some people.
The severity of hypertrophic cardiomyopathy varies widely. Most people with hypertrophic cardiomyopathy have a form of the disease in which the wall (septum) between the two bottom chambers of the heart (the ventricles) becomes enlarged and obstructs blood flow. This is sometimes referred to as hypertrophic cardiomyopathy with obstruction or hypertrophic obstructive cardiomyopathy.
Sometimes hypertrophic cardiomyopathy occurs without significant obstruction of blood flow. However, the heart's main pumping chamber (the left ventricle) may become stiff, which reduces how much blood the ventricle can hold and how much blood gets pumped out to the body with each contraction. Doctors sometimes refer to this as hypertrophic cardiomyopathy without obstruction or nonobstructive hypertrophic cardiomyopathy.
Hypertrophic cardiomyopathy affects men and women equally.
The condition is usually inherited. There's a 50 percent chance that the children of those with hypertrophic cardiomyopathy will inherit the genetic mutation for the disorder. Siblings of those with hypertrophic cardiomyopathy also are at risk. As a result, close relatives of someone with hypertrophic cardiomyopathy are urged to talk to their doctors about getting screened for the disease.
In many people, hypertrophic cardiomyopathy doesn't cause significant health problems. However, in some people, hypertrophic cardiomyopathy can cause severe signs and symptoms, such as shortness of breath, chest pain or fainting.
People with hypertrophic cardiomyopathy are at risk of dangerous abnormal heart rhythms (arrhythmias), such as ventricular tachycardia or ventricular fibrillation. These abnormal heart rhythms can cause sudden cardiac death. Hypertrophic cardiomyopathy is the leading cause of heart-related sudden death in people under 30. Fortunately, such deaths are rare.
Possible complications of hypertrophic cardiomyopathy include:
Preparing for your appointment
You're likely to start by first seeing your family doctor. However, in some cases when you call to set up an appointment, you may be referred to a doctor who specializes in the diagnosis and treatment of heart conditions (cardiologist).
Here's some information to help you prepare for your appointment.
What you can do
For hypertrophic cardiomyopathy, some basic questions to ask your doctor include:
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment at any time that you don't understand something.
What to expect from your doctor
What you can do in the meantime
Tests and diagnosis
A doctor might first suspect hypertrophic cardiomyopathy if he or she hears a heart murmur while listening to the heart. A heart murmur could indicate that the thickened heart muscle is causing abnormal blood flow through the heart.
Echocardiogram is the most common test to diagnose hypertrophic cardiomyopathy. Using echocardiogram images, your doctor can see the thickness of your heart muscle, whether blood flow is obstructed and if your heart valves are moving normally.
An echocardiogram uses sound waves to produce images of the heart. An echocardiogram allows the doctor to see the complicated movement of the heart in motion — ventricles squeezing and relaxing, and valves opening and closing in rhythm with the heartbeat. The doctor can use these images to identify abnormalities in the heart muscle and valves. Types of echocardiograms include:
Additional tests might be done to help look for other effects of hypertrophic cardiomyopathy and help determine what sort of treatment could be needed. These additional tests include:
Testing approaches for first-degree relatives
Because of the complex nature of how your genes interact, genetic tests often don't give a definitive answer. In addition, insurance companies may not cover the testing. Talk with your doctor about whether genetic testing could be an option for you.
If you have a first-degree relative — parent, sibling or child — with hypertrophic cardiomyopathy, experts recommend that you be screened regularly for signs of this condition starting at puberty (about age 12) or when you begin competitive athletics. The recommendation is to have an echocardiogram and electrocardiogram once each year until you reach adulthood (about age 18) and stop competitive athletics. If no evidence of hypertrophic cardiomyopathy is found by the time you reach adulthood, your doctor may recommend adjusting your screening schedule to once every five years.
Treatments and drugs
The goals of treatment for hypertrophic cardiomyopathy are to relieve symptoms and prevent sudden cardiac death in those at high risk.
Treatment options for hypertrophic cardiomyopathy include drugs, surgery or other methods to destroy obstructive heart tissue or implantation of devices to help control heart rhythm.
People with hypertrophic cardiomyopathy who may be candidates for ICD implantation include those with:
Lifestyle and home remedies
Your doctor will recommend a number of key lifestyle restrictions to reduce your risk of hypertrophic cardiomyopathy-related complications. You'll likely need to follow restrictions for your:
Coping and support
Being diagnosed with hypertrophic cardiomyopathy can cause a range of difficult emotions and fears. Like many people with this condition, you're likely to struggle with feelings of grief, fear and anger. These are appropriate responses to the serious changes that come with your diagnosis, including exercise restrictions, a lifelong reliance on medications, fear of death and fear of passing the condition on to your children.
Talk with your doctor if you are feeling hopeless, panicked or unable to cope. It may help to talk with a therapist. In some cases, your doctor also may recommend medications that treat mental health problems such as anxiety and depression.
In other cases, your mental health may benefit most from talking with medical experts, such as your medical care team or a genetic counselor, who can help you understand your risks and find effective ways of coping.
Because hypertrophic cardiomyopathy is inherited, it can't be prevented. However, doctors and scientists are learning more about the genetic mutations that cause the disorder. Though the condition itself can't be prevented, it's important to identify this condition as early as possible to guide treatment and prevent complications.
Preventing sudden death
Unfortunately, because many people with hypertrophic cardiomyopathy don't realize they have it, there are instances where the first sign of a problem is sudden cardiac death. These cases can happen in seemingly healthy young people, including high school athletes and other young, active adults. News of these types of deaths generates understandable attention because they're so unexpected, but parents should be aware these deaths are quite rare.
Still, experts in heart abnormalities generally recommend that those with hypertrophic cardiomyopathy not participate in most competitive sports, with the possible exception of some low-intensity sports. You should talk with your cardiologist about specific recommendations. The use of an implantable cardioverter-defibrillator should not be viewed as a substitute for these recommendations.
Last Updated: 2012-09-07
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