Lisa Marie Presley, the daughter of iconic rock star Elvis Presley, died in January 2023 after suffering a cardiac arrest at the age of 54. Cardiac arrest occurs when the heart suddenly stops pumping blood. It happens when the heart’s electrical system doesn’t work properly, causing the heart to stop pumping blood to the body.

Multiple members of Lisa Marie’s family died from heart disease before the age of 50, including her father, grandmother, and great-uncles. The autopsy on her father found that his heart was almost double the normal size. Genetic testing performed on a hair sample believed to be Elvis’ found that he had genetic changes that cause hypertrophic cardiomyopathy (HCM). HCM causes the heart to enlarge and increases the risk of sudden cardiac death.

For many people, having a family member suffer a sudden cardiac death is the first sign that HCM may run in their family. Although HCM can’t be prevented, it’s important for people at risk for the condition to understand what it is and how it’s passed on.

What Is Familial HCM?

HCM is the most common type of genetic heart disease, affecting about 1 in 200 people worldwide.

In HCM, a mutation (change or variation) in certain genes causes the heart to thicken and get larger — this is called cardiac hypertrophy. These mutations cause the heart to work harder to move blood throughout your body. The additional strain can also cause the heart muscle to thicken.

When this mutation runs in the family, it is referred to as familial HCM. If the change does not run in the family, it is known as nonfamilial HCM.

What Causes HCM?

About 60 percent of people with HCM have familial HCM, according to Circulation: Arrhythmia and Electrophysiology. The remaining 40 percent have a nonfamilial type.

The mutated genes are inherited in an autosomal dominant pattern. This means that only one parent needs to pass on the gene for a child to be affected. Scientists have discovered people with HCM have mutations in genes that are involved in the structure of the sarcomere (heart muscle) or that regulate how the heart muscle contracts and relaxes.

Some of these genes include:

• MYH7 — Gives structural support to heart muscles
• MYBPC3 — Gives structural support and regulates muscle contraction
• TNNT2 and TNNI3 — Make troponins, which control muscle contraction and relaxation

People without a known genetic mutation can still have HCM. Additionally, if you have a mutation in one of these genes, it doesn’t necessarily mean you’ll develop the disease.

Symptoms of HCM

People experience symptoms of HCM in different ways, even within the same family. Some people don’t have any symptoms at all.

Sometimes, the first sign of HCM is fainting during exercise, especially for people younger than 35 years old. People with HCM may also feel breathlessness or chest pain while exercising. Other symptoms include dizziness, lightheadedness, or palpitations (feeling like your heart is skipping a beat).

There can also be more serious consequences. Some people can have changes in their heart rhythm — this is called arrhythmia. Ventricular arrhythmias are the primary cause of sudden cardiac death in people with HCM. The risk of sudden death is increased for people with HCM, even without any symptoms.

Your Family History and HCM

About 70 percent of sudden cardiac deaths from HCM happen in people not previously diagnosed with HCM, according to a 2019 study in Circulation. Your family history may provide some insight into your risk of HCM. Because many people with HCM don’t have any symptoms, it can be difficult to know if it runs in your family.

A MyHeartDiseaseTeam member commented, “There is a gene for these heart conditions. It is good to know your family history.”

If you have a parent, sibling, or child with HCM, your risk increases from 1 in 200 to 1 in 2 because of the way HCM is inherited.

A detailed family history can help your cardiologist diagnose HCM. You should include the following family members you are biologically related to:

• Parents
• Brothers and sisters
• Grandparents
• Aunts and uncles
• Grandchildren
• Nieces and nephews

Some important things to look for while collecting your family history include:

• Known heart problems such as heart failure, heart attacks, arrhythmias, or coronary artery disease (CAD)
• High blood pressure
• Diabetes
• Stroke
• Pacemakers
• Heart-related surgeries
• Exercise-induced asthma, which can sometimes be mistaken for symptoms of HCM

Genetic Screening

If you, like Lisa Marie Presley, have family members who suffered sudden cardiac death — especially at an early age — you may want to ask your doctor about genetic screening for HCM. Genetic screening for HCM involves using a blood sample to test for the mutated genes that can cause HCM.

Other Inherited Diseases That Can Cause Cardiac Arrest

HCM isn’t the only heart disease that can cause sudden cardiac arrest. Parents can pass down other diseases that may increase your risk.

Familial Dilated Cardiomyopathy

Familial dilated cardiomyopathy (FDC) is a genetic heart condition that can cause sudden cardiac death. In FDC, a genetic mutation makes the heart muscles thinner and weaker. This results in one or more heart chambers becoming dilated (larger).

People with FDC will often have symptoms similar to those of heart failure, such as shortness of breath, heart palpitations, and tiredness. Although FDC is rare, researchers estimate that as many as 1 in 250 people could have FDC, according to the Journal of the American Medical Association.

Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) increases a person’s risk of heart attacks and strokes at a young age. About 50 percent of men with FH have a heart attack by the age of 50, and 30 percent of women with FH have a heart attack by the age of 60. About 1 in 300 people have FH, according to the journal Arteriosclerosis, Thrombosis, and Vascular Biology.

Hypercholesterolemia means high cholesterol. Although some people have high cholesterol from what they eat, genetics can also play a role. People with FH have inherited changes that affect how the body regulates cholesterol. The result is increased levels of low-density lipoprotein (LDL) cholesterol — also known as bad cholesterol. A normal LDL cholesterol level is less than 100 milligrams per deciliter. People with FH will often have LDL levels over 190 milligrams per deciliter.

Atherosclerosis can develop when the excess LDL cholesterol builds up in your arteries and partially or completely blocks them, resulting in a stroke or heart attack.

Some MyHeartDiseaseTeam members are living with FH. One member asked, “Are any of you fighting genetic cholesterol? What’s your treatment?”

For people with FH, diet and lifestyle changes are usually not enough to lower their cholesterol. Diagnosing and treating FH reduces the risk of heart attack and other coronary heart diseases by 80 percent.

Familial Arrhythmias

A heart arrhythmia is an irregular heart rhythm caused by problems in the heart’s electrical signals. People with arrhythmias have a higher risk of sudden cardiac death. Familial arrhythmias, or hereditary arrhythmias, are rare. The most common types of inherited arrhythmias include:

• Long QT syndrome (LQTS)
• Catecholaminergic polymorphic ventricular tachycardia (CPVT)
• Brugada syndrome

Talk With Others Who Understand

MyHeartDiseaseTeam is the social network for people with heart disease and their loved ones. On MyHeartDiseaseTeam, more than 56,000 members come together to ask questions, give advice, and share their stories with others who understand life with heart disease.

Are you living with HCM? Do you have a family history of HCM? How do you manage your symptoms? Share your experience in the comments below, or start a conversation by posting on your Activities page.