Hypertrophic cardiomyopathy (HCM) is usually caused by a gene mutation that is passed down in families.

If you have a parent with the condition, you have a 50/50 chance of inheriting it. In the same way, if you have it, each of your children has a 50/50 chance of being born with this mutation.

Because it’s a genetic condition, it’s a good idea to talk with your health care team about your family history. For example, have any family members—especially parents or siblings—died suddenly without a clear cause?

Understanding Your Family’s Risk

If you have a parent, brother, sister, or child (first-degree relative) with hypertrophic cardiomyopathy (HCM), your care team may recommend you get screened for the condition. Screening can involve genetic testing or imaging tests, or both.

These steps help ensure that those with a higher chance of having the condition are monitored and treated if needed.

Counseling can help you assess your family’s risk of HCM and decide on testing. A counselor can review the pros and cons of genetic testing, how the test results will be used, and whether it will be covered by your insurance plan.

If you have HCM, the main reason to perform genetic testing is to find out if genetic screening would be useful for your children, siblings, or parents. But genetic tests don’t always detect the mutation for HCM.

Heart imaging tests and other assessments are usually recommended after 12 years of age. Thickening of the heart muscle often doesn’t appear until adolescence. But it may start earlier if the child is having symptoms or plays competitive sports.

When to screen also could be guided by your family’s specific history or preference. Talk to your care team to be sure you understand whether you or your family members should be screened and how often. 

Exams and Tests

Your care team may suspect you have hypertrophic cardiomyopathy (HCM) if:

• Your parent, sibling or child has it
• You have certain symptoms
• Your clinician hears a heart murmur when listening to your heart

Imaging and other tests can show signs that the heart muscle is unusually thick. These tests, in particular an echocardiogram, are used to confirm a diagnosis.

These tests are usually ordered because of family history of the disease or to rule out other diseases, including valve problems.  

Common tests include:

• Echocardiogram: This test uses sound waves (ultrasound) to look at the structure of your heart. It can show if your heart muscle is too thick. It also shows how well the chambers and valves in your heart are pumping.
• Electrocardiogram (ECG): This test uses sensors placed on your chest and sometimes legs to record the electrical activity of the heart. It can detect irregular heartbeats and signs your heart muscle is enlarged. You may be given a Holter or wireless monitor to wear for a day or more to measure electrical signals from your heart over a longer time.
• Exercise or stress testing: This test allows your doctor to see how your heart performs during activity (usually on a treadmill or exercise bike). Your doctor will watch your blood pressure, heart rate, how your heart beats and any symptoms you feel.
• Magnetic resonance imaging (MRI) of the heart: This test can detect a thickening of the left ventricular wall. It may help identify areas not seen in an echocardiogram.

In some cases, genetic testing may also be used to find out if you, your children, siblings or parents carry the gene mutation that causes HCM.