Hypertrophic cardiomyopathy (HCM) is a disease in which the heart muscle becomes abnormally thick (hypertrophied). The thickened heart muscle can make it harder for the heart to pump blood.
Hypertrophic cardiomyopathy often goes undiagnosed because many people with the disease have few, if any, symptoms and can lead normal lives with no significant problems. However, in a small number of people with HCM, the thickened heart muscle can cause shortness of breath, chest pain or problems in the heart's electrical system, resulting in life-threatening abnormal heart rhythms (arrhythmias) or sudden death.
Signs and symptoms of hypertrophic cardiomyopathy may include one or more of the following:
A number of conditions can cause shortness of breath and heart palpitations. It's important to get a prompt, accurate diagnosis and appropriate care. See your doctor if you have a family history of HCM or any symptoms associated with hypertrophic cardiomyopathy.
Call 911 or your local emergency number if you have any of the following symptoms for more than a few minutes:
Hypertrophic cardiomyopathy is usually caused by abnormal genes (gene mutations) that cause the heart muscle to grow abnormally thick.
In most people with hypertrophic cardiomyopathy, the muscular wall (septum) between the two bottom chambers of the heart (ventricles) becomes thicker than normal. As a result, the thicker wall may block blood flow out of the heart. This is called obstructive hypertrophic cardiomyopathy.
If there's no significant blocking of blood flow, the condition is called nonobstructive hypertrophic cardiomyopathy. However, the heart's main pumping chamber (left ventricle) may become stiff. This makes it hard for the heart to relax and reduces the amount of blood the ventricle can hold and send to the body with each heartbeat.
People with hypertrophic cardiomyopathy also have an abnormal arrangement of heart muscle cells (myofiber disarray). This can trigger arrhythmias in some people.
Hypertrophic cardiomyopathy is usually passed down through families (inherited).
If you have a parent with hypertrophic cardiomyopathy, you have a 50% chance of having the genetic mutation for the disease.
Parents, children or siblings of a person with hypertrophic cardiomyopathy should ask their doctors about screening for the disease.
Many people with hypertrophic cardiomyopathy (HCM) don't have significant health problems. But complications of hypertrophic cardiomyopathy can include:
There is no known prevention for hypertrophic cardiomyopathy. But it's important to identify the condition as early as possible to guide treatment and prevent complications.
If you have a first-degree relative — a parent, sibling or child — with hypertrophic cardiomyopathy, doctors may recommend genetic testing to screen for the condition. However, not everyone with HCM has a currently detectable mutation. Also, some insurance companies may not cover genetic testing.
If genetic testing isn't done, or if the results aren't helpful, then your doctor may recommend echocardiograms on a regular basis if you have a family member with hypertrophic cardiomyopathy. Adolescents and competitive athletes should be screened once a year. Adults who don't compete in athletics should be screened every five years.
Your doctor will examine you and ask questions about your signs, symptoms, and medical and family history.
Your doctor will likely order tests to diagnose hypertrophic cardiomyopathy (HCM) or rule out other conditions that can cause similar symptoms.
Echocardiogram. An echocardiogram is commonly used to diagnose hypertrophic cardiomyopathy. This test uses sound waves (ultrasound) to see if your heart's muscle is abnormally thick. It also shows how well your heart's chambers and valves are pumping blood.
Sometimes, an echocardiogram is done while you exercise, usually on a treadmill. This is called an exercise stress test. Treadmill stress tests are commonly used to diagnose people with hypertrophic cardiomyopathy.
The goal of hypertrophic cardiomyopathy treatment is to relieve symptoms and prevent sudden cardiac death in people at high risk. Your specific treatment depends on the severity of your symptoms. Together, you and your doctor will discuss the most appropriate treatment for your condition.
Medications can help reduce how strong the heart muscle squeezes and slow the heart rate so that the heart can pump blood better. Medications to treat hypertrophic cardiomyopathy and its symptoms may include:
Several different surgeries or procedures are available to treat cardiomyopathy or its symptoms. They range from open-heart surgery to implantation of a device to control your heart rhythm.
Septal myectomy. This open-heart surgery may be recommended if medications do not improve your symptoms. It involves removing part of the thickened, overgrown wall (septum) between the heart chambers. Septal myectomy helps improve blood flow out of the heart and reduces backward flow of blood through the mitral valve (mitral regurgitation).
The surgery may be done using different approaches, depending on the location of the thickened heart muscle. In one type, called apical myectomy, surgeons remove thickened heart muscle from near the tip of the heart. Sometimes the mitral valve is repaired at the same time.
Lifestyle changes can reduce your risk of complications related to hypertrophic cardiomyopathy. Your doctor may recommend lifestyle changes, including:
Women who have hypertrophic cardiomyopathy can generally have normal pregnancies. However, if you have hypertrophic cardiomyopathy, your doctor may recommend that you see a doctor experienced in caring for women with high-risk conditions during your pregnancy.
Being diagnosed with hypertrophic cardiomyopathy can cause a range of difficult emotions. Like many people with this condition, you may experience feelings of grief, fear and anger. These responses are appropriate to the lifestyle changes that come with your diagnosis.
To cope with your condition:
You may be referred to a doctor trained in diagnosing and treating heart conditions (cardiologist). Here's some information to help you prepare for your appointment.
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment.
Your doctor is likely to ask you a number of questions. Being ready to answer them may make time to go over points you want to spend more time on. You may be asked:
Before your appointment, ask your family members if any relatives have been diagnosed with hypertrophic cardiomyopathy or have experienced unexplained, sudden death. It will help your doctor to know as many details as possible about your family medical history.
If exercise makes your symptoms worse, avoid strenuous exercise until you have seen your doctor and received specific exercise recommendations.
© 1998-2021 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved.