What Is Hypertrophic Cardiomyopathy?
Hypertrophic cardiomyopathy (HCM) is a condition in which your heart muscle, or myocardium, becomes thicker than normal. This interferes with your heart’s ability to pump blood.
In most cases, HCM doesn’t cause any symptoms. People with HCM are generally able to lead normal lives. However, some cases can become serious. Serious cases may develop either slowly or suddenly.
HCM occurs in about one in every 500 people in the United States.
Recognizing the Symptoms of HCM
Many people with HCM don’t experience any symptoms. However, the following symptoms may occur during physical activity:
- chest pain
- shortness of breath
Other symptoms that might occur, at any time, include:
- shortness of breath
- heart palpitations, which are pounding or fluttering heartbeats
- high blood pressure
What Causes HCM?
HCM is typically an inherited condition. Defective genes can cause your heart muscle to thicken. You have a 50 percent chance of inheriting one of these genes if one of your parents is affected by HCM.
Inheriting the gene doesn’t necessarily mean that you’ll have symptomatic disease. HCM follows a dominant pattern of inheritance. However, symptoms don’t always develop in people with the defective gene.
Other possible causes of HCM include aging and high blood pressure. In some cases, the cause of HCM is never identified.
How Is HCM Diagnosed?
Different tests can be used to diagnose HCM.
Your doctor will listen for a heart murmur or unusual heartbeats. Heart murmurs may occur if thickened heart muscle disrupts blood flow to your heart.
This is the most common diagnostic test for HCM. An echocardiogram creates images of your heart using sound waves. Your doctor will look for any unusual movements.
An electrocardiogram is used to measure the electrical activity in your heart. HCM can cause abnormal results.
A Holter monitor is a portable electrocardiogram that you can wear throughout the day. Your doctor will have you wear it for 24 to 48 hours. This allows your doctor to see how your heartbeat changes during different activities.
A cardiac MRI uses a magnetic field to produce detailed images of your heart.
This test is used to measure the pressure of blood flow in your heart and look for blockages. To perform this test, your doctor will place a catheter in one of your arteries in your arm or near your groin. The catheter is carefully threaded up through your arteries to your heart. Once it reaches your heart, dye is injected so your doctor can take detailed X-ray images.
How Is HCM Treated?
Treatment for HCM focuses on relieving symptoms and preventing complications, especially sudden cardiac death. The methods used depend on your:
- activity level
- heart function
Beta-blockers and calcium channel blockers relax your heart muscle. Relaxation helps it work better.
If you have an irregular heart rhythm, your doctor might prescribe antiarrhythmic medications, such as amiodarone.
You might need to take antibiotics before dental procedures or surgery to lower your risk of infective endocarditis.
A septal myectomy is an open-heart surgery that’s done to remove part of your thickened septum. The septum is the heart muscle wall between your two lower heart chambers, which are your ventricles. It helps improve blood flow through your heart.
A septal myectomy is done only if medications don’t reduce your symptoms.
Septal ablation involves the use of alcohol to destroy part of your thickened heart muscle. The alcohol is injected through a catheter placed in the artery that supplies the part of your heart that’s being treated.
A septal ablation is often done in people who can’t have a septal myectomy.
If you have an irregular heart rate and rhythm, a tiny electronic device called a pacemaker can be placed under the skin on your chest. The pacemaker helps regulate your heart rate by sending electrical signals to your heart.
This procedure is less invasive than septal myectomies and ablations. It’s also usually less effective.
Implantable Cardioverter Defibrillator (ICD)
An implantable cardioverter defibrillator (ICD) is a small device that uses electric shocks to track your heartbeat and fix dangerous, abnormal heart rhythms. It’s placed inside your chest.
ICD is often used in people who have a high risk of sudden cardiac death.
If you have HCM, your doctor may recommend lifestyle changes to reduce your risk of complications. This includes:
- eating a healthy diet
- keeping your weight at a healthy level
- doing low-intensity physical activities
- limiting alcohol intake, since alcohol can cause abnormal heart rhythms
Potential Long-Term Complications of HCM
Many people with HCM will never have any serious health problems caused by it. However, HCM can cause severe complications in some people. The most common complications of HCM are:
Sudden Cardiac Arrest
Sudden cardiac arrest occurs when your heart suddenly stops working. This condition is also called “sudden cardiac death.” This is typically caused by a rapid heart rhythm known as ventricular tachycardia. Without emergency treatment, sudden cardiac arrest can be fatal. HCM is the leading cause of sudden cardiac death in people who are under 30.
You might be at higher risk for sudden cardiac death if you have one or more of the following:
- a family history of sudden cardiac death
- poor heart function
- severe symptoms
- a history of irregular heart rhythms with a fast heart rate
- a history of fainting on several occasions and you’re young
- an unusual blood pressure response to physical activity
When your heart doesn’t pump the amount of blood that your body needs, you’re experiencing heart failure.
This diagnosis means your heart muscle has become weak and enlarged. The enlargement makes your heart work less effectively.
When the inner lining of your heart or your heart valves become infected, it’s known as infective endocarditis. This can happen when bacteria or fungi enter your bloodstream and get into your heart. Infective endocarditis can cause tissue scarring, holes, or growths in your heart valves. It can be fatal without treatment.
Coping and Getting Support
Having a disease like severe HCM can raise your risk of emotional problems. Some people have trouble coping with the adjustments they have to make, such as restricting exercise and relying on medication for the rest of their lives.
If you’re having difficulty coping with HCM, your doctor might recommend seeing a therapist or joining a support group. You might also benefit from medications used to treat anxiety or depression.