Hypertrophic Cardiomyopathy (HCM) | Heart and Vascular

Heart and Vascular Care

Hypertrophic Cardiomyopathy (HCM)

Our heart specialists offer the latest therapies to help you manage HCM while protecting your heart.

Medically reviewed on May 25, 2023.

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What Is Hypertrophic Cardiomyopathy?

Hypertrophic cardiomyopathy (HCM) is a disease that causes thickening of the heart walls (hypertrophy). This thickening stiffens the heart walls, making it harder you’re your heart to pump blood. Your heart also can’t hold as much blood, meaning it sends less blood to the rest of your body.

You may have obstructive or non-obstructive HCM. Hypertrophic obstructive cardiomyopathy (HOCM) occurs when thickening of the heart walls obstructs (blocks) blood flow out of your heart. Two-thirds of people diagnosed with HCM have this type. The remaining one-third have non-obstructive HCM, which doesn’t significantly block blood flow out of your heart.

Although most people with either form of HCM can live a normal life, the condition can be serious for some. It can often go undiagnosed. Our team of expert cardiologists and cardiac surgeons diagnose and treat HCM as early as possible to help protect your heart.


Hypertrophic Cardiomyopathy Symptoms

You may not experience any symptoms with HCM. Or you may only notice symptoms when exercising or doing physical activity. Sometimes HCM symptoms develop only as the conditions worsens over time.

Common Symptoms

Common symptoms of HCM include:

  • Chest pain, especially after physical exertion
  • Difficulty breathing
  • Fainting
  • Heart murmurs
  • Irregular heartbeat (arrhythmia)
  • Lightheadedness
  • Swelling in your lower body, torso or veins in your neck
  • Tiredness or weakness

Emergency Symptoms

Call 911 immediately if you experience heart attack symptoms, such as:


Hypertrophic Cardiomyopathy Causes

There are two main causes of hypertrophic cardiomyopathy, which include:

Familial Hypertrophic Cardiomyopathy

In most people, HCM is a hereditary condition passed down through families. People who have one parent with HCM have a 50% chance of inheriting the gene change that causes the disease.

Heart Damage

Certain medical conditions or lifestyle choices can harm your heart. This damage can lead to HCM or other types of cardiomyopathy.


Risk Factors for Thickening of the Heart

There are a couple things that can increase your risk for hypertrophic cardiomyopathy, including:

Family History of Genetic Heart Conditions

If you have a parent, sibling or child with this disease, ask your health care provider about genetic testing options to learn your risk.


Some types of cardiomyopathy, including HCM, are common among specific age groups. For example, HOCM commonly affects people in their 30s. Specialists often diagnose HCM when people reach middle age (36 to 44 years old).


Hypertrophic Cardiomyopathy Diagnosis and Testing

Our cardiologists specialize in diagnosing and treating HCM. Your physician will do a physical exam of your body. They may ask questions about your medical history, your family’s medical history and recent symptoms.

Your physician may order several tests to confirm HCM, such as:

  • Ambulatory monitor (Holter monitor), which records your heart’s activity over a period of time
  • Blood tests to check your electrolyte levels or look for genetic issues
  • Electrocardiogram (ECG or EKG) to detect your heart’s electrical activity and measure its time and duration
  • Genetic testing to show if the disease runs in your family
  • Stress tests to understand if physical exertion triggers or worsens the HCM

You may also undergo imaging tests, such as:

  • Cardiac catheterization, in which physicians place a tube (catheter) in your coronary arteries to understand how your heart is working 
  • Chest X-ray to produce pictures of the inside of your chest and show if your heart is enlarged 
  • MRI to show detailed pictures of your heart and how well your heart’s chambers and valves are pumping blood 

Hypertrophic Cardiomyopathy Treatments at UC Davis Health

At UC Davis Health, we provide evidence-based care for HCM at any stage of life. Our expert team includes cardiologists, cardiothoracic surgeons, nurses, pharmacists and social workers. Together, we create a treatment plan that fits with your needs.

If your physician has diagnosed you with HCM, but you don’t have symptoms, we may decide together that you don’t need treatment right away. Your treatment plan will depend on the severity of HCM and whether it is obstructive or non-obstructive. Other existing medical issues can also affect your treatment choices. We may recommend:


HCM often makes it hard for blood to flow throughout your body. We may prescribe medications to help, such as:

  • Beta blockers to slow your heart rate if you have an irregular heartbeat (arrhythmia)
  • Blood thinners to thin the blood to help prevent blood clots
  • Calcium channel blockers to relax your blood vessels (blood pressure) and make it easier for your heart to pump blood
  • Diuretics to remove excess sodium and fluids from your body  

Lifestyle Changes 

If your physician diagnoses you with HCM or it runs in your family, heart-healthy choices can boost your heart and overall health. Consider:

  • Limiting fluid and salt (sodium) intake
  • Exercising with care (talk with your physician beforehand)
  • Limiting or avoiding alcohol consumption
  • Maintaining a healthy weight
  • Managing chronic conditions like diabetes or sleep apnea
  • Quitting smoking or other tobacco use

Check out our heart health education classes

Alcohol Septal Ablation

We are the only center in the Sacramento are to offer alcohol septal ablation for HCM. During this nonsurgical procedure, our expert physicians inject ethanol (alcohol) into the artery that supplies blood to the thickened part of your heart muscle. A small part of the muscle dies, shrinking the tissue to its normal size. This process allows the blood to flow again with less blockage.


We may recommend surgery for HCM if medications, nonsurgical procedures and lifestyle changes don’t work.

The most common surgeries place special devices into your body to correct irregular heartbeats (arrhythmias) and improve blood flow. These permanent devices include:

  • Cardiac resynchronization therapy (CRT) device: A physician implants the CRT device into the lower chambers of your heart (ventricles). The device helps your ventricles contract together rather than at different times.
  • Implantable cardioverter defibrillator (ICD): A device that maintains your heart’s normal rhythm. It sends a shock to your heart if it detects an irregular heartbeat.
  • Pacemaker: A small device that uses electrical pulses to prompt your heart to beat normally.

Other surgical procedures available are: 

  • Septal myectomy: This surgery improves blood flow by removing the part of the heart’s thickened wall (septum) bulging into your heart’s left ventricle. Surgeons often reserve this option for younger people or for when medications don’t work.
  • Heart transplant: A surgeon replaces your diseased heart with a healthy donor heart. A heart transplant is a last-resort treatment. Most transplant recipients are in end-stage heart failure.   

"Genetic Testing," Columbia University Department of Medicine, https://www.columbiacardiology.org/patient-care/hypertrophic-cardiomyopathy-center/about-hypertrophic-cardiomyopathy/genetic-testing

"Temporal Trend of Age at Diagnosis in Hypertrophic Cardiomyopathy," American Heart Association Journals. https://www.ahajournals.org/doi/10.1161/CIRCHEARTFAILURE.120.007230

Who does it affect?

1 in 500People affected by familial HCM

Risk factors

50%Chance of passing down or inheriting the gene that causes HCM

Sources: American Heart Association: Overview of Inheritance

Centers for Disease Control and Prevention (CDC): Hypertrophic Cardiomyopathy (HCM) and Family Health History of Sudden Death

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