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Hypertrophic Cardiomyopathy

Piedmont’s Hypertrophic Cardiomyopathy Program offers complete multidisciplinary evaluation and treatment for patients with hypertrophic cardiomyopathy, from medical to surgical treatment options.

What is hypertrophic cardiomyopathy?

Hypertrophic Cardiomyopathy (HCM) is a genetic cardiac disease in which the heart muscle (myocardium) becomes abnormally thickened (hypertrophied), most commonly as a result of a genetic mutation. A thickened heart can make it harder for the heart to pump enough blood to meet the body's needs. The thickened muscle can also affect one of the leaflets of the mitral valve, which separates the heart's left atrium and left ventricle. The valve leaflet may become leaky, allowing blood to move backward from the left ventricle into the left atrium instead of forward to the body.

Most people with HCM have a form of the disease in which the wall (septum) between the two pumping chambers of the heart (ventricles) becomes thickened and restricts blood flow out of the heart, obstructing the flow of blood (obstructive HCM). Obstruction refers to impeded blood flow out of the left ventricle, which creates higher pressures in the heart. Obstruction is common in typical HCM and is present in more than two-thirds of patients at rest or with physical activity.

Hypertrophic cardiomyopathy is hereditary. Since HCM is a genetic disease, it can be transmitted to a family's consecutive generations of affected relatives. Direct family members of patients with HCM should be screened for the disease.

At Piedmont Heart, we offer complete multidisciplinary evaluation and treatment options for patients and families with HCM.

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Attention patients: Learn about cardiac myosin inhibitors, the newest treatment option for HCM.


How does cardiomyopathy differ from other heart disorders?
  • HCM can, and often does, occur in the young.
  • The condition affects about 600,000 Americans, though the genetic predisposition may be seen in more than 1 in 500 people.
  • HCM can be present genetically without demonstrating physical findings or characteristics.
  • Requires careful screening of first-degree family members.
What are the symptoms and complications of hypertrophic cardiomyopathy?

HCM can go undiagnosed because many people with the disease have few, if any, symptoms and can lead normal lives with no significant problems. However, some people with HCM can experience symptoms. The following are the most common symptoms of HCM; however, each person may experience symptoms differently, and these symptoms are not specific to HCM and can be seen with other health problems:

  • Shortness of breath, especially during exercise
  • Dizziness or fainting
  • Abnormal heart rhythms (arrhythmias) or palpitations
  • Chest pain, especially during exercise
  • Heart murmur, which a doctor might detect while listening to your heart
  • Abnormal ECG, which a doctor might detect on evaluation

Many people with HCM don't experience significant health problems, but some people experience complications, including:

  • Atrial Fibrillation: The abnormal thickened heart muscle, as well as the abnormal structure of heart cells, can disrupt the normal functioning of the heart's electrical system, resulting in fast or irregular heartbeats. Atrial fibrillation can also increase your risk of developing blood clots, which can travel to your brain and cause a stroke.
  • Sudden Cardiac Death: Ventricular tachycardia and ventricular fibrillation are rare complications of HCM and can cause sudden cardiac death. People with HCM are at an increased risk of sudden cardiac death, although such deaths are rare. Sudden cardiac death is estimated to occur in about 1% of people with HCM annually. HCM can cause heart-related sudden death in people of all ages, but the condition most often causes sudden cardiac death in people under the age of 30. HCM is the most common cause of sudden death in young competitive athletes (e.g., soccer or basketball players).
  • Obstructed Blood Flow: In some people with HCM, the thickened heart muscle obstructs the blood flow leaving the heart. Obstructed blood flow can cause shortness of breath with exertion, chest pain, dizziness and fainting spells.
  • Dilated Cardiomyopathy: Over time, thickened heart muscle may become weak and ineffective in some people with HCM. The ventricle enlarges (dilated), and its pumping ability becomes less forceful.
  • Mitral Valve Problems: The thickened heart muscle can affect the function of the heart's mitral valve. As a result, blood can leak backward into the left atrium (mitral valve regurgitation), possibly leading to worsening symptoms.
  • Heart Failure: The thickened heart muscle can become too stiff to effectively fill with blood. As a result, your heart can't pump enough blood to meet your body's needs. This can lead to the syndrome of congestive heart failure.
How is hypertrophic cardiomyopathy tested and diagnosed?

In order to determine if you have HCM and your optimal treatment plan, you may undergo some or all of the following testing. Your doctor will review your medical and family history, discuss your signs and symptoms, and conduct a physical examination. The tests and treatment needed for patients are individually determined.

  • Echocardiogram (or “Echo”): Echocardiography is a simple, noninvasive and readily available test that utilizes ultrasound to see if your heart muscle is abnormally thick, if your blood flow is obstructed or your heart valves are functioning normally.
    • Transthoracic Echocardiogram: A small device (transducer) is pressed against your chest wall and aims a sound beam to pick up “echoes” or images of the heart muscle and valves. This is the primary test done to determine if HCM is present and if so, what type and to what degree.
    • Transesophageal Echocardiogram: A flexible tube containing a transducer is guided down your throat and into the tube connecting your mouth and stomach (esophagus). From there, the transducer can obtain more-detailed images of your heart. This test may be recommended if it's difficult to get a clear picture of your heart with a standard echocardiogram or if the doctor wants to further examine your mitral valve. This test is done rarely in HCM.
  • Electrocardiogram (“ECG” or “EKG”): An electrocardiogram is a test that measures the electrical activity of your heart and should be performed in all patients when considering a diagnosis of hypertrophic cardiomyopathy. Wires (electrodes) attached to adhesive pads are applied to your skin to measure and record electrical impulses signals as they travel through your heart. An ECG can detect enlarged chambers of your heart and abnormal heart rhythms. Abnormal ECG tracings are common in HCM patients.
  • Treadmill Stress Test: Your heart rhythm, blood pressure and symptoms are monitored while you walk on a treadmill. Your doctor may recommend a treadmill stress test to evaluate symptoms, determine your exercise capacity and determine if exercise provokes abnormal heart rhythms. Treadmill stress tests are commonly used in people with HCM.
  • Stress “Exercise” Echocardiogram: Treadmill Stress Tests are sometimes performed with echocardiography. If your transthoracic echocardiogram shows a thickened heart muscle, you may also have an exercise echocardiogram. This will decipher whether you develop obstruction when your heart rate increases during physical activity and if so how much obstruction is present. This is intended to mimic circumstances under which you may experience limiting symptoms daily with activities such as walking upstairs or hills and may guide future treatment options.
  • Holter Monitor: A small, portable, wearable ECG device that continuously records your heart’s activity during normal day-to-day activities. It can be worn for various lengths of time, ranging from 24 hours to several weeks. The monitor detects if there are any abnormal rhythms of the heart and helps to identify and correlate symptoms of dizziness, palpitations or passing out and evaluate for any potentially asymptomatic abnormal rhythms. This may allow the healthcare provider to better stratify one’s risk for sudden cardiac death.
  • Cardiac Magnetic Resolution Imaging (MRI): A common test used to diagnose and assess many diseases and conditions, including heart disease. The MRI uses magnetic fields to create detailed images of your heart. This test is often used in addition to echocardiograms as it provides a more detailed visualization of heart muscle walls and offers a more precise measurement of heart muscle thickness. MRI can also give more detailed information about heart muscle thickening, valve function, and abnormal heart muscle scarring.
  • Cardiac Catheterization: In this procedure, a catheter is inserted into a blood vessel, usually in your wrist, arm or groin area. The catheter is then carefully threaded to your heart chambers under the guidance of an X-ray machine. In addition to measuring pressures in your heart, cardiac catheterization is used to obtain X-ray images (angiograms) of your heart and blood vessels. A contrast dye is injected through the catheter to help visualize your heart and blood vessels.
  • Genetic Testing: Since HCM is a genetic disease, it can be transmitted to each consecutive generation. If you have a first-degree relative (a parent, sibling or child) with HCM and a documented disease-causing mutation, doctors may recommend that you be screened for the condition either with genetic testing or simply with Echocardiography and ECG. Genetic testing is performed by drawing blood and sending it to a lab for processing, with results coming in 4-6 weeks. Consultation with your cardiologist is recommended to help you determine whether genetic testing is a good option for you.
How is hypertrophic cardiomyopathy treated?

Most patients affected with HCM have a normal life expectancy without symptoms or disability or major treatment interventions. About one-third of all HCM patients do not have obstruction to blood flow out of the left side of the heart either at rest or with exercise. Of these patients, many will develop either no, or only mild symptoms limiting physical activity. Such mild symptoms can be controlled with medication. Specific treatment for HCM will be determined by your physician based on:

  • Age, overall health, and medical history
  • Extent of the disease
  • Tolerance for specific medications, procedures or therapies
  • Expectations for the course of the disease
  • Your opinion or preference
  • Symptoms


Many HCM patients successfully control their symptoms solely with medications. Typical medications for HCM include Beta blockers, calcium channel blockers, heart rhythm medications, blood thinners and new Myosin Inhibitors. Your physician may recommend medications to accomplish the following:

  • Decrease the workload of the heart
  • Decrease the oxygen requirements of the heart
  • Regulate irregular heartbeats

Surgical treatment options

A small percentage of patients will experience unrelenting severe symptoms that become unacceptable for quality of life despite optimal use of available medications. When medication treatments are ineffective or further treatment is required, you may be a candidate for procedures that will relieve both obstruction and symptoms. These treatments may include:

  • Surgical Septal Myectomy: This procedure removes a small amount of muscle from part of the ventricular septum (the muscular partition between the left and right ventricular cavities). This has the effect of reducing pressures in the heart to normal. This is offered to patients who experience significant limitations during physical activity and are unresponsive to medical drug treatment. This is associated with low surgical risk when performed in experienced HCM referral centers. This surgery dramatically improves or eliminates symptoms and improves outcomes in most patients.
  • Alcohol Septal Ablation (ASA): ASA is an alternative to surgical septal myomectomy to reduce pressure gradients in patients with HCM. This procedure uses catheters to identify the blood vessel that feeds the abnormally thickened heart muscle. Then, using a special catheter, alcohol is instilled into the blood vessels to damage the heart muscle and reduce the thickened part of the heart muscle. This procedure reduces obstruction but does not address any potential valve abnormalities associated with HCM. This procedure is typically used in patients who are not good candidates for surgical septal myomectomy.
  • Permanent Pacemaker (PPM) or Artificial Internal Defibrillator (AICD): Patients with HCM can have heart rhythm abnormalities that require either a PPM or AICD. A device permanently inserted under the skin, capable of pacing the heart, sensing potentially lethal arrhythmias, and possibly shocking the heart back to normal rhythm to prevent sudden cardiac death. Only a small percentage of HCM patients are at increased risk for these arrhythmias.
  • Heart Transplantation: In a very small percentage of patients with HCM, the progression of HCM results in extensive irreversible heart scarring. This can result in progressive weakening of the heart muscle, which, in its end stage, can require heart transplantation to reverse heart failure symptoms and prolong life.
What causes hypertrophic cardiomyopathy? HCM is caused by genetic abnormalities and is inherited. 
Is hypertrophic cardiomyopathy preventable? Because HCM is inherited, it can't be prevented. Identifying the condition as early as possible is important to guide treatment and prevent complications.
When should I consider HCM as a possible diagnosis in me or my family member?
  • If you have suggestive symptoms such as chest pain, shortness of breath, dizziness, fainting or a heart murmur detected on an exam.
  • If you have a first-degree family member with hypertrophic cardiomyopathy.
  • If you or a family member has been diagnosed with HCM, you should undergo an evaluation by one of our HCM specialists.


Call 911 or your local emergency number if you experience any of the following symptoms for more than a few minutes:

  • Rapid or irregular heartbeat

  • Difficulty breathing

  • Chest pain

Hypertrophic cardiomyopathy information for patients

Visit the Hypertrophic Cardiomyopathy Association for more resources and information at www.4hcm.org.

Hypertrophic cardiomyopathy information for physicians

For information on clinical identifiers, diagnostic testing, and management,  visit the Provider Resources page.

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