Welcome to the Minneapolis Heart Institute Foundation’s® Hypertrophic Cardiomyopathy Center (HCM)
The HCM Center at the Minneapolis Heart Institute Foundation® is world-renowned for its expertise in Hypertrophic Cardiomyopathy. Led by Barry J. Maron, MD, the center conducts research and offers advice to individuals diagnosed with HCM. The following information provides more information on the condition, diagnostic tests and potential treatments.
About Dr. Barry J. Maron
Dr. Maron is a world-renowned cardiologist and expert on hypertrophic cardiomyopathy, or HCM, a genetic disease that occurs in approximately one in 500 people. It is estimated that as many as 700,000 Americans are afflicted with the disease.
Maron joined the Minneapolis Heart Institute Foundation® in 1993, and has been the director of its hypertrophic cardiomyopathy program for more than 20 years. His research initiatives have included the diverse clinical and pathologic aspects of hypertrophic cardiomyopathy in collaboration with top physicians and researchers across the globe. In September 2013, the Foundation hosted the fifth international HCM summit in Minneapolis, which was attended by 250 clinicians, researchers, healthcare providers and patients from 16 countries and 29 states.
Hypertrophic cardiomyopathy has garnered headlines over the years as the leading cause of sudden cardiac arrest in the United States in young athletes, and Maron is widely recognized for his research and leadership in this area. He recently chaired an expert panel convened by the American College of Cardiology and the American Heart Association, which in September 2014 released a new scientific statement regarding screening for young people, aged 12-25. The panel recommended that physicians use a 14-element cardiovascular screening checklist to determine whether a young patient is at risk for congenital and genetic heart disease, rather than performing a costly and often-ineffective electrocardiogram. If the 14-point screening turns up any potential issues, additional tests may then be ordered.
In addition to his work with the Foundation, Maron currently serves as adjunct professor of medicine at both the Mayo Clinic and Tufts School of Medicine. He has authored 904 original peer-reviewed articles, book chapters and other contributions to the literature, as well as 325 abstracts and seven books, including the well-regarded “Hypertrophic Cardiomyopathy: For Patients, Their Families and Interested Physicians.”
Maron graduated from Occidental College in Los Angeles in 1963 and received his M.D. degree from Tulane University in New Orleans in 1968. After completing his cardiology fellowship at Johns Hopkins Hospital in 1973, he served for 21 years as a senior investigator in the cardiology branch of the National Institutes of Health before joining the Foundation. Among Maron’s numerous other awards are the Distinguished Alumnus Award from Tulane School of Medicine; Life Achievement Awards from European Society of Cardiology, Japanese Circulation Society and Israeli Heart Society; the American Heart Association Heart and Stroke Award, the Morgagni Award (Padua, Italy), the Simon Dack Scholarship Award, and the Distinguished Clinical Scientist Career Award of the American College of Cardiology.
What is HCM?
Hypertrophic cardiomyopathy (HCM) is a common genetic heart disease affecting as many as 1:200 Americans. In hearts with HCM, the heart muscle (myocardium) becomes abnormally thick, or hypertrophied, which can lead to a variety of complications. However, HCM is a treatable condition compatible with normal or extended longevity, and the risk of sudden death has decreased through the use of implantable defibrillators. Now, HCM-related mortality has declined to 0.5 percent per year.
HCM Symptoms and Causes
Because many people with HCM have few or no symptoms, the disease often goes undiagnosed. Symptoms of HCM may include one or more of the following:
- Excessive shortness of breath
- Chest pain
- Pounding or rapid heartbeats
- A heart murmur as detected by a physician
Any of these symptoms should trigger contact with a cardiologist.
To diagnose HCM, your cardiologist will review your medical and family history, discuss your signs and symptoms, conduct a physical examination and may order several tests. An imaging test called an echocardiogram shows whether the heart muscle is abnormally thick, if blood flow is blocked, and whether the heart valves are moving properly.
Other tests for HCM include:
- Holter monitor. An ambulatory ECG records the heart’s activity continuously, usually over one to two days, to detect occult arrhythmias.
- Treadmill stress test. Patients walk on a treadmill while heart rhythm and blood pressure are monitored, allowing doctors to evaluate symptoms, determine exercise capacity, and monitor whether exercise provokes abnormal heart rhythms. If HCM symptoms are present but a resting echocardiogram does not show obstructed blood flow, a treadmill stress tests may be performed with echocardiography in order to show obstruction provoked with exercise.
- Electrocardiogram (ECG). Electrical impulses from the heart are measured by electrodes attached to adhesive pads on the skin. This allows detection of abnormal heart rhythms and suggests enlarged heart chambers.
- Cardiac MRI. A cardiac MRI adds precision to echocardiography using radio waves and magnetic fields to create images of the heart.
- Cardiac catheterization. In this procedure, a catheter is inserted into a blood vessel, usually in the groin area. The catheter is then carefully threaded to the heart chambers, using X-ray as guidance, to measure pressures in the heart. In addition, a dye is injected to provide an image of the heart and blood vessels. This procedures is used in HCM only occasionally and selectively.
HCM Treatment Options
For HCM patients, the goal of treatment is to prevent sudden cardiac death in high-risk patients, while also relieving symptoms in others to allow for maintenance of a normal lifestyle. Of course, specific treatment methods will vary depending on the severity of each patient’s condition and precise disease expressions.
Treatment options include:
- Medications. The specific medication prescribed will depend on the depend on the symptoms that need to be treated. Beta-blockers: metoprolol (Lopressor, Toprol), propranolol (Inderal, Innopran XL) or atenolol (Tenormin), are commonly administered to reduce symptoms of shortness of breath, as are calcium channel blockers such as verapamil (Verelan, Calan, Covera-HS) or disopyramide (Norpace). To control heart rhythm, atrial fibrillation specifically, drugs such as amiodarone (Cordarone, Pacerone) may be used. About 25% of HCM patients have atrial fibrillation, requiring blood thinners such as warfarin (Coumadin, Jantoven), dabigatran (Pradaxa), rivaroxaban (Xarelto) or apixaban (Eliquis) to reduce risk of blood clots.
- Septal myectomy. Surgical septal myectomy is an open-heart procedure in which the surgeon removes part of the thickened septum between the ventricles, improving blood flow and reducing obstruction and mitral regurgitation and reversing heart failure and symptoms.
A myectomy may be recommended if prescribed medications do not relieve severe symptoms caused by obstruction. Heart transplant is rarely necessary in HCM.
- Septal ablation. In this procedure, a catheter is placed in an artery that supplies blood to part of the upper septum and alcohol is injected through the catheter, destroying a small piece of the thickened heart muscle. This procedure is performed in a catheterization laboratory procedure (not open heart surgery) which may also reduce symptoms and obstruction. Possible complications with this procedure include heart block — a disruption of the heart’s electrical system — requiring permanent implantation of a pacemaker. Alcohol ablation is considered only an alternative option to myectomy, in patients not considered optimal candidates for surgery or who reject that option through personal preferences.
- Implantable cardioverter-defibrillator (ICD). An ICD may be recommended to high-risk HCM patients to prevent sudden death from serious rhythm disorders such as ventricular tachycardia or ventricular fibrillation. An ICD is a small device that is implanted in the chest (similar to a pacemaker) and continuously monitors heart rhythm. If a life-threatening arrhythmia occurs, the ICD delivers precisely calibrated electrical shocks to restore normal heart rhythm.