September 5, 2006
A University of Michigan Health Minute update on important health issues.
Families can fight back against inherited
sudden-death heart condition, U-M expert says
HCM affects 1 in 500 people, and is the top cause of death in young athletes
ANN ARBOR, MI – Both sides of Catherine Gray’s family tree hang heavy with heart problems, going back at least two generations. So when her heart started acting up soon after she hit age 50, Catherine got nervous.
A careful heart exam showed the root of her problems – and perhaps those of others in her family tree. She has a genetic condition called hypertrophic cardiomyopathy, or HCM, which causes her heart muscle to grow too thick. The extra muscle blocked blood flow out of her heart when she was active, and made her short of breath just from walking in the mall.
As many as one in every 500 Americans has HCM and many do not know they have it. HCM is an inherited, or genetic, condition that affects 50 percent of the children of people who suffer from it. And although most people with HCM genes won’t develop problems as severe as Catherine’s, it’s the most common cause of sudden death in young individuals — and can suddenly kill people who may have no symptoms at all.
Now, a combination of better diagnosis, treatment and genetic testing is starting to help people with HCM, and their families, fight back against their inherited risk. People who have a family history of sudden heart-related deaths, or a relative with a diagnosis of HCM, can get a clearer picture of the risks that they and their children face. And that can help shape both treatment and preventive steps.
After her diagnosis, Catherine first got help from a combination of medications prescribed by her doctor in Flint, Mich. He also monitored her heart regularly using ultrasound. But as her condition got worse, she headed to the University of Michigan Cardiovascular Center for more aggressive treatment.
After a minimally invasive procedure that used an injection of alcohol to reduce the amount of extra muscle in her heart, she feels like a new woman. Before, she says, “I was afraid my heart may stop all together. And I was just really, really miserable,” with a constant feeling like someone was choking her. But, she continues, “After the procedure, it was like someone released me. The pressure was gone. Whatever had me around the throat was gone. I have a new lease on life.”
Catherine’s story is proof that proper care can give HCM patients a chance at better quality of life and peace of mind, says Sharlene Day, M.D., who directs the U-M’s HCM Clinic, one of only seven specialized programs for HCM patients in the nation. It brings together heart and genetic specialists who treat both adults and children.
But getting diagnosed is still a challenge, says Day, an assistant professor of cardiovascular medicine at the U-M Medical School.
“Because so many people with HCM may not know they have it because they don’t experience symptoms, it can often be difficult to make the diagnosis,” she explains. “Many individuals don’t experience symptoms early on, but may develop them later in life.”
Some people with HCM find out they have it by chance, when they’re having other tests done, she says. Others might seek their doctor’s advice about heart-related symptoms they’ve been feeling — such as a “jumpy” heart rhythm, chest pain or shortness of breath — and find out through tests that they have HCM. And still others only find out when they tell their doctors that several people in their family have experienced sudden heart-related deaths, or have been diagnosed with HCM.
“There is a certain population of people who should definitely go to their doctor to be screened for HCM,” says Day. “These people include anyone who has a family history of sudden cardiac death, especially among relatives under age 55, or anyone with a family history of HCM. In addition, any individual who experiences breathlessness when they exercise, chest pain or heart palpitations, or has lost consciousness without an obvious explanation, should go in to see their doctor.” This holds true for children and teenagers, as well as adults, she says.
Several tests can identify HCM. The initial one performed on many patients is an echocardiogram, or ultrasound of the heart, which can reveal thickening of the heart muscle and identify areas where blood flow may be obstructed from leaving the heart.
With a thorough history, physical examination and some simple noninvasive testing, doctors can tell someone with HCM how high their risk of sudden death is — around 1-in-100 each year for most HCM patients, but as high as 6-in-100 per year for others. That risk level will play a part in determining what treatments patients receive.
Now, genetic testing is starting to emerge as a way to determine how many relatives of an HCM patient also inherited the same genes and might be at risk. “As we learn more about genetics and we perform genetic testing on patients, we hope we can improve the management of patients, and in the future, identify people who carry the genetic mutation but do not yet have HCM,” Day says. “In that way, we hope we can even find ways to prevent the development of the disease.”
The U-M team is one of few in the nation offering genetic testing for HCM patients and their families, and they are conducting a research study to analyze genetic results from many families. Day and her colleagues are also performing laboratory research to understand why HCM gene mutations cause heart muscle to thicken, and to test new strategies for reversing or slowing the process.
Until genetic treatments are available, HCM patients and their family members have many options. Both adults and children who have symptoms or are at a high risk of sudden death can take medications that keep their heart beating steadily, and have regular tests to monitor their heart muscle and its electrical activity. Implanted devices called defibrillators — which can detect a dangerous heart-rhythm problem instantly and restore normal rhythm — can help prevent sudden death in adults and children with serious HCM-related rhythm problems.
For those whose heart muscle is getting in the way of blood flow, the U-M team and other specialized teams around the country offer procedures to reduce it.
The minimally invasive option, which U-M’s Mauro Moscucci, M.D., performed on Catherine Gray, is called alcohol septal ablation. Another option to reduce the amount of excess heart tissue involves an open-heart operation called a myectomy.
In the end, Catherine says getting the right diagnosis and treatment has made all the difference in the world to her. She’s now back out in her beloved garden, where she’s even enjoying being able to bend over and pull weeds without feeling like her heart will stop. She also has more energy to devote to her grandchildren. And as HCM research and care move forward, those grandchildren may be able to avoid the problems she has faced.
Patients and families interested in the U-M Hypertrophic Cardiomyopathy clinic may call the U-M Cardiovascular Center patient hotline at 888-287-1082. For more information on the Web, visit www.med.umich.edu/cvc.
Facts about hypertrophic cardiomyopathy, or HCM:
- Hypertrophic cardiomyopathy, whose name literally means “thickened heart muscle disease”, is an inherited condition that causes the cells of the heart muscle to grow abnormally. It is abbreviated HCM.
- About one in every 500 Americans has HCM. There are more than 400 genetic mutations known to be associated with HCM.
- Not everyone who inherits an HCM genetic mutation will develop the condition; some may have no symptoms, others in the same family may have severe problems. Children born to a person who has HCM have a 50 percent chance of inheriting the same mutation that may cause HCM.
- HCM can increase a person’s chance of dying suddenly from a violent interruption in the electrical activity of the heart; this is called sudden cardiac death and is different from a “heart attack.” The increased risk of sudden death due to HCM varies from person to person, but a thorough history taking and proper testing can help determine an individual’s risk.
- HCM is the leading cause of sudden heart-related death among young individuals, particularly among young athletes who die while exercising. It causes one-third of such deaths. Former Boston Celtics basketball player Reggie Lewis is just one example of an athlete who died suddenly due to HCM.
- People who have lost family members to sudden heart-related death, especially if the death was in someone under age 55, should talk to their doctors about whether they should be tested for HCM. Some such deaths might have been assumed to be a heart attack.
- HCM can cause symptoms that include irregular heartbeat, heart palpitations, shortness of breath, chest pain, fatigue, and more. It can also cause patients to lose consciousness. Anyone who has experienced such symptoms, especially if they occurred during exercise, should talk to their doctor about being tested for HCM.
Find out more on the web at:
U-M Cardiovascular Center HCM Clinic
National Institutes of Health: Cardiomyopathy:
Written by Kara Gavin
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