June 1, 2006
U-M launches program for inherited heart muscle condition that causes many sudden cardiac deaths
Hypertrophic cardiomyopathy runs in families, and affects 1 in 500 people
New clinic brings together all of U-M's diagnosis, treatment & genetic services
ANN ARBOR, MI – Some families seem cursed with especially bad heart health, losing members of several generations in sudden, tragic deaths at young ages.
But for many of these families, the ‘curse’ may actually be an inherited genetic disease that makes the heart muscle grow abnormally thick — and increases the risk of sudden cardiac death or other heart problems for many members of the family. As many as one in every 500 Americans may have this condition, called hypertrophic cardiomyopathy, and many may not know they have it.
Now, the University of Michigan Cardiovascular Center has launched a new, comprehensive Hypertrophic Cardiomyopathy Clinic that will help patients, and their families, understand their risk and receive effective treatment. It’s one of only seven programs in the country devoted specifically to hypertrophic cardiomyopathy, or HCM.
The U-M program unites a broad range of physicians and others who already help hundreds of HCM patients each year. The new coordinated approach to testing, diagnosis, and treatment will give patients access to the full range of options – including genetic testing and counseling that can help an entire family. It will also help families participate in research that seeks to improve HCM care for the future.
“HCM is a complex disease, but we know so much more about it than we used to, including its genetic roots and effective treatments,” says Sharlene Day, M.D., the U-M cardiologist who directs the new effort. Day, who has treated many HCM patients while also studying the disease in the laboratory, adds, “We hope to provide patients and their families access to the best quality of care, incorporating new knowledge and tools for diagnosis and treatment”
The U-M team includes adult and pediatric cardiologists, cardiac surgeons, geneticists and genetic counselors who will cooperate to evaluate and treat HCM patients and their family members. Among them are experts in echocardiography, the ultrasound test that is used to diagnose HCM, and experts in the use of risk-reducing medications. The team also includes doctors experienced in performing minimally-invasive and open-heart operations to pare down the thickened heart muscle, and specialists in treating problems of the heart’s electrical system, which is often disturbed by HCM.
The team includes children’s heart specialists from the Michigan Congenital Heart Center, because HCM can develop in late childhood or adolescence. In fact, HCM is estimated to cause one-third of sudden cardiac deaths among athletes in their teens and 20s. In these especially high-profile situations, which often occur on the playing field or court, the heart muscle suddenly stops when extreme physical exertion sets off violently irregular rhythms. Former Boston Celtics basketball player Reggie Lewis is just one example of an athlete felled by HCM.
However. Day cautions, most cases of HCM aren’t severe enough to pose a high risk of sudden death. The difficulty comes in identifying which patients are at a high risk. Unfortunately, this risk is not related at all to the degree of symptoms that patients may experience. Many people with HCM have no or only mild symptoms, and yet some are still at increased risk of dying suddenly without warning.
More than 400 genetic mutations in genes that affect the development, function and organization of heart muscle cells, have been found to cause HCM. But echocardiograms, and modern genetic testing, make it possible to determine which family members are at risk.
Because of the way HCM runs in families, a child of a person with the disease has a 50 percent chance of developing it. However, the severity of the disease varies greatly between different family members, even if they all carry the same genetic mutation. U-M geneticists and genetic counselors work with families to determine who needs screening, and how often individuals of any age will need follow-up examinations and tests.
If the screening identifies family members who have an especially high risk of sudden cardiac death, doctors may recommend implanted cardioverter defibrillators, or ICDs, which are devices that can detect sudden severe heart arrhythmias, and immediately shock the heart back into rhythm. U-M is a top center for ICD therapy in children and adults.
The thickened, stiffened heart muscle that develops in HCM patients can sometime interfere with the flow of blood out of the heart to the body, causing patients to feel breathless or experience chest pain with physical exertion. Medications to regulate the heart’s activity can often help keep this in check, and ease the symptoms that many HCM patients experience.
But in some patients, a procedure to remove the obstructing tissue may be needed to relieve severe symptoms. U-M cardiologists are experienced at performing a minimally invasive, catheter-based procedure called alcohol septal ablation that can reduce the amount of excess heart tissue. And U-M cardiac surgeons are adept at removing even larger amounts of excess tissue in operations called myectomies. In extreme cases, a heart transplant may be necessary; U-M is a top-ranked heart transplant center.
The U-M team also offers experience in telling HCM apart from other heart conditions that can mimic it – including the heart-muscle enlargement that is often seen in competitive athletes, and in people with high blood pressure.
In addition to advanced clinical care, HCM patients and families seen at the new U-M clinic will have the opportunity to take part in research that may lead to better care for tomorrow’s patients.
Currently, U-M researchers are recruiting HCM patients, and healthy people with at least one relative who has HCM, for a study aimed at finding out more about the genetics of HCM. Laboratory research that looks at what goes wrong in the heart muscle cells of HCM patients is now under way. And U-M researchers will analyze data from large numbers of HCM patients to look for patterns and determine what treatments are most effective.
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.
For more information on HCM and related issues, visit the Hypertrophic Cardiomyopathy Association.
Written by Kara Gavin
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