Hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (also called HCM) is a disease that causes your heart muscle to become abnormally thick, making it harder for the heart to pump blood.

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About hypertrophic cardiomyopathy (HCM)

Hypertrophic cardiomyopathy is most often caused by abnormal genes in the heart muscle that make the walls of the heart chamber (left ventricle) contract harder than normal. This extra work causes walls to thicken over time (hypertrophy) and start to become stiff and, in almost 2 out of 3 patients, leads to high pressures in the heart, often referred to as outflow tract obstruction.

There are several different types of hypertrophic cardiomyopathy, but the presence of outflow tract obstruction is a major feature that helps determine treatment options.

It’s estimated that one out of every 200 to one out of every 500 people has hypertrophic cardiomyopathy, and most of those cases go undiagnosed.

While some cases can eventually progress into more serious conditions, people with HCM can live into their 90s. The key to improved longevity is knowing how to properly manage the disease.

Signs, symptoms, and risks of HCM

Signs and symptoms

Signs and symptoms of hypertrophic cardiomyopathy may include one or more of the following:

  • Chest pain, especially during exercise.
  • Fainting, especially during or just after exercise or exertion.
  • Heart murmur, which a doctor might detect while listening to your heart.
  • Sensation of rapid, fluttering or pounding heartbeats (palpitations).
  • Shortness of breath, especially during exercise.

Risk factors

Hypertrophic cardiomyopathy is usually inherited. People with parents who have HCM have a 50% chance of having the genetic mutation for the disease.

In addition to genetic markers, there are certain diseases, conditions or factors can raise your risk for cardiomyopathy. They include:

Complications of hypertrophic cardiomyopathy

Even though most people with hypertrophic cardiomyopathy don’t have experience significant health problems, complications can arise, including:

  • Atrial fibrillation. As the heart muscle thickens, it can adversely impact the heart’s electrical system, causing fast or irregular heartbeats. Because blood isn’t properly pumped out of the heart, atrial fibrillation can also increase the risk of developing blood clots, which can travel to the brain and cause a stroke.
  • Outflow tract obstruction. In many cases, the heart muscle becomes so thick that it increases the pressure in the heart and increases the effort needed to pump blood, causing chest pain, dizziness, fainting spells and shortness of breath with exertion.
  • Mitral valve problems. If the heart muscle grows to be too thick, it can block blood from leaving the heart and prevent the valve between the left atrium and left ventricle (mitral valve) from closing as it should. When this happens, blood can leak back into the left atrium (called mitral valve regurgitation) and can cause symptoms to get worse.
  • Dilated cardiomyopathy. This condition, in which the heart muscle has become so thick that its pumping mechanism is weak and ineffective, occurs with very small number of HCM patients. The more the ventricle enlarges (or dilates), the less forceful its pumping ability becomes.
  • Heart failure. When the heart muscle becomes too thick, it also can become too stiff to effectively pump enough blood into the heart. Heart failure occurs when your heart can no longer pump enough blood to meet your body’s needs.
  • Sudden cardiac death. In rare cases, hypertrophic cardiomyopathy can cause heart-related sudden death in people of all ages. This is due to dangerous fast electrical rhythms from the bottom of the heart, termed ventricular tachycardia and ventricular fibrillation. Because hypertrophic cardiomyopathy often goes undiagnosed, sudden cardiac death may be the first indication there was a problem.

How is hypertrophic cardiomyopathy diagnosed?

Most people with hypertrophic cardiomyopathy don’t exhibit any symptoms, so typically it is diagnosed when someone goes to see their doctor after experiencing symptoms like chest pain, fainting or shortness of breath after exercise or physical exertion. During the examination, the doctor will ask questions about their signs, symptoms, and medical and family history.

Tests

In order to diagnose hypertrophic cardiomyopathy, and also to rule out other conditions that cause similar symptoms, your doctor will typically order certain tests.

  • Echocardiogram. One of the most common tests used to diagnose hypertrophic cardiomyopathy is called an echocardiogram. An echocardiogram uses sound waves (ultrasound) to determine two factors: if your heart’s muscle is abnormally thick and to see how well your heart’s chambers and valves are pumping blood.

Sometimes, your doctor will choose to have you perform an exercise stress test, meaning you take the test while exercising on a treadmill. These stress tests are commonly used to diagnose hypertrophic cardiomyopathy.

  • Electrocardiogram (ECG or EKG). In this test, doctors attach sensors (electrodes) to adhesive pads and place them on your chest or legs. Designed to measure the electrical signals from your heart, ECGs can show signs of hypertrophic cardiomyopathy, like heart thickening and abnormal heart rhythms. In some cases, when your doctor wants to record your heart’s activity continuously over a couple of days, they will connect you to a portable ECG, called a Holter monitor.
  • Cardiac MRI. Using powerful magnets and radio waves, a cardiac MRI creates images of your heart muscle that shows how your heart and heart valves work. This test is often done with an echocardiogram.
  • Genetic testing. Modern genetic testing methods are affordable and often covered by insurance. After genetic counseling, many patients undergo genetic testing that can affect testing and follow up for their family.

Treatments for HCM

Because there is no cure for hypertrophic cardiomyopathy, treatments are designed to address and alleviate symptoms and assess your risk of sudden cardiac arrest. Your doctor will determine the course of your treatment based upon the severity of your symptoms. The two most common treatment options are medication and surgery.

Medications

Your doctor can prescribe medications designed to reduce the strength of your heart muscle’s contractions, as well as to slow your heart rate, so that it can pump blood more efficiently.

Medications to treat hypertrophic cardiomyopathy and its symptoms may include:

  • Beta blockers such as metoprolol (Lopressor, Toprol-XL), propranolol (Inderal, Innopran XL) or atenolol (Tenormin).
  • Calcium channel blockers such as verapamil (Verelan, Calan SR) or diltiazem (Cardizem, Tiazac).
  • Heart rhythm drugs such as disopyramide (Norpace).
  • Blood thinners such as warfarin (Coumadin, Jantoven), dabigatran (Pradaxa), rivaroxaban (Xarelto), apixaban (Eliquis), or edoxaban (Lixiana) to prevent blood clots if you have atrial fibrillation.

Medications to avoid
You may be told to avoid certain medications, such as nitrates, because they lower blood pressure, or digoxin, because it increases the force of the heart’s contraction.

Surgeries or other procedures

Depending on the severity of your symptoms, your doctor has several different treatment options available, ranging from open-heart surgery to implantation of a device to control your heart’s rhythm.

  • Septal myectomy. If medication doesn’t improve symptoms, doctors may suggest septal myectomy, an open-heart surgery that removes part of the thickened wall (septum) between the heart chambers. This surgery can increase blood flow out of the heart while reducing mitral regurgitation, the backward flow of blood through the mitral valve.
  • Septal ablation. This procedure uses a catheter to inject alcohol into the artery supplying blood to the septum, thus destroying the thickened heart muscle. Possible complications include disruption of the heart’s electrical system (heart block), which requires implantation of a pacemaker.
  • Implantable cardioverter-defibrillator (ICD). The ICD is a small device that is implanted in your chest like a pacemaker. It continuously monitors your heartbeat. In the event you experience a life-threatening arrhythmia, the ICD restores normal heart rhythm with precisely calibrated electrical shocks. ICDs have been shown to be effective in preventing sudden cardiac death, a condition that occurs in a small number of people with HCM.

Frequently asked questions about HCM

Is hypertrophic cardiomyopathy a progressive disease?

Most patients with hypertrophic cardiomyopathy have no symptoms and live normal lives. A few patients develop serious symptoms and find that those symptoms get progressively worse over time. These patients will sometimes develop an arrhythmia (irregular heartbeat) or find that their heart muscle has continued to thicken as they age, making the heart have to work harder to pump blood.

What is the difference between heart failure and cardiomyopathy?

Cardiomyopathy describes a primary abnormality of the heart muscle. Heart failure (also known as congestive heart failure) is the syndrome of shortness of breath, fatigue and swelling that people experience when they have a heart that doesn’t pump blood as well as it should – this can be from many reasons, including cardiomyopathy, or a past heart attack or leaky heart valves. Over time, the heart often becomes too weak or stiff to fill and pump efficiently, resulting in death.

Can high blood pressure cause thickening of the heart?

High blood pressure or aging can be causes of hypertrophy. Knowing that hypertension can worsen the symptoms of cardiomyopathy, it’s imperative you strive to maintain a healthy blood pressure (an average of <130/80 mm Hg). If you take blood pressure medication, be sure to follow your doctor’s direction, as some blood pressure medications can worsen obstruction in certain people.

Can stress cause hypertrophic cardiomyopathy?

Excessive stress is never a healthy thing and is known to raise blood pressure. Elevated blood pressure can, in turn, increase the risk of cardiomyopathy.

To better manage stress, actively address it by making sure you get plenty of sleep and regular exercise as instructed by your doctor. You might even try relaxation techniques like deep breathing and yoga.

What foods are good for cardiomyopathy?

As with most things health related, eating a healthy diet can have a positive impact on heart health as well. A heart healthy diet includes a variety of fruits, vegetables, whole grains, and lean meats and fish. At the same time, it’s important to avoid fatty or processed meats and sugary drinks

Is walking good for cardiomyopathy?

It’s important to consult your physician before starting any exercise regimen. With that being said, daily light exercise is recommended as safe for most people with hypertrophic cardiomyopathy and is a great way to help manage symptoms. Over time, it’s been proven to help reduce heart rate and blood pressure.

How do you manage hypertrophic cardiomyopathy?

Knowing there is no cure for hypertrophic cardiomyopathy, the focus becomes on ways to best manage it. The type of hypertrophic cardiomyopathy treatment your doctor will prescribe depends on:

  • Whether you have an outflow tract obstruction (high pressures in the heart that make it more difficult for the heart to pump blood).
  • How your heart is functioning.
  • Your symptoms.
  • Your age and activity level.
  • Your risk of sudden cardiac arrest.

The goal of treatment is to minimize symptoms and reduce the risk of complications, such as heart failure and sudden cardiac death. To embrace a holistic approach, treatment includes risk identification and regular follow-up, lifestyle changes, medications and procedures, as needed.

Certain lifestyle changes can help you properly manage hypertrophic cardiomyopathy:

  • Fluid and sodium restrictions. Ask your doctor for specific fluid and dietary guidelines if heart failure symptoms are present. Also inquire about alcoholic beverages and caffeinated products.
  • Exercise. Make sure to discuss exercise options with your doctor. Moderate exercise and participation in athletics do not appear to increase the risk of death and are safe for most patients. High intensity exercise or participation in competitive sports should be discussed on an individual basis with your doctor.
  • Regular follow-up visits. Proper management means regular follow up. Patients with hypertrophic cardiomyopathy should regularly check in with their cardiologist, as recommended, to monitor their condition.
Does hypertrophic cardiomyopathy affect children?

Although HCM is fairly common in adults, hypertrophic cardiomyopathy is rare in children. Children with HCM don’t typically have symptoms until late childhood or early teens. If they do experience symptoms, the most common is low stamina with shortness of breath and chest pain during exercise. As they age, the heart’s chronic overwork over time can cause heart enlargement and congestive heart failure symptoms.

Infection prevention. Children with hypertrophic cardiomyopathy are at increased risk for subacute bacterial endocarditis (SBE), an infection of the heart caused when bacteria enter the blood stream. This impacts children with heart defects because of the altered flow of blood through the heart and/or abnormal heart valves. There are many causes of SBE, but it often occurs after dental work or medical procedures on the GI or respiratory tract. Doctors will typically prescribe an antibiotic before these procedures in order to prevent SBE.

References

MedlinePlus: National Library of Medicine. Familial hypertrophic cardiomyopathy (https://medlineplus.gov/genetics/condition/familial-hypertrophic-cardiomyopathy/)

MedlinePlus: National Library of Medicine. Hypertrophic cardiomyopathy (https://medlineplus.gov/ency/article/000192.htm)

National Center for Biotechnology Information (NCBI): National Library of Medicine. Hypertrophic Obstructive Cardiomyopathy (https://www.ncbi.nlm.nih.gov/books/NBK430820/)