What Is Cardiomyopathy?


Cardiomyopathy refers to problems with your heart muscle that can make it harder for your heart to pump blood. There are many types and causes of cardiomyopathy, and it can affect people of all ages.

Depending on the type of cardiomyopathy that you have, your heart muscle may become thicker, stiffer, or larger than normal. This can weaken your heart and cause an irregular heartbeat, heart failure, or a life-threatening condition called cardiac arrest.

Some people have no symptoms and do not need treatment. Others may have shortness of breath, tiredness, dizziness and fainting, or chest pain as the disease gets worse. Your doctor will ask about your symptoms and do tests to diagnose cardiomyopathy. Echocardiography is the most common test.

Cardiomyopathy can be caused by your genes, other medical conditions, or extreme stress. It can also happen or get worse during pregnancy. Many times, the cause is not known.

What causes cardiomyopathy?

Cardiomyopathy can be inherited or acquired.

  • “Inherited” means that your parents passed the gene for the disease on to you. Mutations, or changes in the genes that control how your heart is formed, can cause your heart not to develop properly. Hypertrophic cardiomyopathy and arrhythmogenic cardiomyopathy are often inherited types of the disease.
  • “Acquired” means that you weren’t born with the disease, but you developed it due to another disease or condition. Conditions that damage your heart can lead to cardiomyopathy.

Cardiomyopathy may also be a symptom of another condition. Many times, the cause is not known.

What raises the risk of cardiomyopathy?

Cardiomyopathy can develop in people of all ages, races, and ethnicities. Sometimes, other medical conditions or lifestyle habits can raise your risk of cardiomyopathy.

Risk factors you can control

  • Drinking a lot of alcohol regularly (more than 2 drinks per day for men or 1 drink per day for women)
  • Using cocaine or amphetamines
  • Very stressful situations, which can raise your risk of takotsubo cardiomyopathy, also called broken heart syndrome, especially if you have other risk factors

Risk factors you can’t control

  • Age: Some types of cardiomyopathy are more common in certain age groups.
    • Arrhythmogenic cardiomyopathy is more common in teens and young adults.
    • Dilated cardiomyopathy is more common in adults between 20 and 60 years old.
    • Hypertrophic cardiomyopathy is more common in people in their 30s.
    • Takotsubo cardiomyopathy is more common in women after menopause.
  • Family history of cardiomyopathy or other heart conditions
  • Chemotherapy or radiation treatment for cancer
  • Other medical conditions:
    • Diseases that affect how well your muscles work, such as Duchenne muscular dystrophy
    • Diseases that cause substances to build up in your heart, such as sarcoidosis or amyloidosis
    • Heart inflammation from endocarditis, myocarditis, or pericarditis
    • Infections, such as viral hepatitis and HIV
    • Obesity, diabetes, or other problems with your metabolic system
    • Thyroid disease and other problems with your hormone levels

Some people with cardiomyopathy never have any symptoms. Other people may not have symptoms until the condition gets worse.

Common symptoms include the following:

  • Shortness of breath
  • Chest pain, especially after physical activity or heavy meals
  • Tiredness even after resting
  • Dizziness and fainting
  • Arrhythmias (irregular heartbeats)
  • Heart murmurs (extra or unusual sounds heard during a heartbeat)

Babies and young children may experience vomiting, diarrhea, difficulty eating and breathing, fussiness, and poor growth.


If your cardiomyopathy has caused heart failure, you may also have swelling in your stomach area, hands, legs, and feet. You may also have these symptoms if you have cardiomyopathy during pregnancy.


Hypertrophic cardiomyopathy: This type of cardiomyopathy causes the heart muscle to become larger and thicker than normal. The thickened areas can block the ventricles (the lower chambers of the heart), making it harder for the heart to pump blood.

Dilated cardiomyopathy: This is a common condition that happens when the ventricles in the heart weaken and get larger. The weakened ventricles don’t pump well, and this makes your heart work harder. 

Arrhythmogenic cardiomyopathy: This rare condition develops when fatty or scarred tissue replaces the normal muscle tissue in the right ventricle. This can cause an irregular heartbeat (arrhythmia). Arrhythmogenic cardiomyopathy usually affects teens or young adults, and it raises the risk for cardiac arrest. In fact, it is the most common cause of sudden death in young people and in athletes.

Restrictive cardiomyopathy: This rare type of cardiomyopathy causes the ventricles to stiffen, but the walls of the heart do not thicken. Because of this, the ventricles don’t relax and don’t fill with enough blood to pump to the rest of the body. Transthyretin amyloid cardiomyopathy is a rare type of restrictive cardiomyopathy that is more common in African-American men.

Left ventricular noncompaction: This rare type of cardiomyopathy occurs when the left ventricle develops muscle that is both smooth, as it should be, and loose, like a thick web. The loose muscle can extend into the left ventricle. This weakens the heart muscle and prevents the heart from pumping enough blood to the rest of the body.

Takotsubo cardiomyopathy, or broken heart syndrome: This rare condition develops when extreme stress causes the heart muscle to stop working properly. This condition affects more women than men and is more common after menopause.

Diagnostic tests

To diagnose cardiomyopathy, your doctor may order one or more tests.

  • Blood tests check the levels of certain substances in your blood that are raised when you have cardiomyopathy or complications such as heart failure.
  • Heart tests, such as imaging tests, echocardiography, and stress tests, check the size and shape of your heart and how well it is working.
  • Genetic testing is important when one or more of your close relatives has cardiomyopathy or another heart condition that runs in families.  A genetic counselor can help you find out if your cardiomyopathy is inherited.

Procedures: Your doctor may order one of these medical procedures to confirm your diagnosis:

Cardiac catheterization: Cardiac catheterization is a medical procedure used to diagnose and treat some heart conditions. During cardiac catheterization, a long, thin, flexible tube called a catheter is put into a blood vessel in your arm, groin or upper thigh, or neck. The catheter is then threaded to your heart.

Coronary angiography: Coronary angiography is a procedure that uses contrast dye, usually containing iodine, and X-ray pictures to detect blockages in the coronary arteries that are caused by plaque buildup. Blockages prevent your heart from getting oxygen and important nutrients.

This procedure is used to diagnose heart diseases or after abnormal results from tests such as an electrocardiogram (EKG) or an exercise stress test. If you are having a heart attack, coronary angiography can help your doctors plan your treatment.

Heart biopsy: A heart biopsy, or myocardial biopsy, is used to diagnose some types of cardiomyopathy. For this test, your doctor will remove a very small piece of your heart muscle to check for signs of cardiomyopathy. This can be done during cardiac catheterization.


Medicines: The following medicines can help treat your symptoms. If your doctor prescribes a medicine, they have determined that the benefits outweigh the risks for your condition.

  • Medicines to remove extra sodium and fluid from your body: These include diuretics and aldosterone antagonists. These medicines lower the amount of blood that the heart must pump. Very high doses of diuretics may cause low blood pressure, kidney disease, and worsening heart failure symptoms. Side effects of aldosterone antagonists can include kidney disease and high potassium levels. 
  • Medicines to relax your blood vessels and make it easier for your heart to pump blood: These include angiotensin converting enzyme (ACE) inhibitors, angiotensin II receptor blockers, and combination hydralazine/isosorbide dinitrate, which is used to treat heart failure in African Americans.  Possible side effects include headaches, cough, low blood pressure, and kidney disease.
  • Medicines to slow your heart rate, such as beta blockers, calcium channel blockers, and ivabradine: You may need one of these medicines if you have an irregular heartbeat (arrhythmia).These medicines make it easier for your heart to pump blood. Possible side effects include a slow or irregular heart rate, high blood pressure, and fuzzy vision or seeing bright halos. They can also make some arrhythmias worse.
  • Medicines to balance your electrolyte levels: These can help your heart work better. Side effects include kidney disease and high potassium levels in your blood.
  • Blood thinners (anticoagulants): These medicines help prevent blood clots. The medicines can raise your risk of serious bleeding.
  • Digoxin: This is used to treat a fast or irregular heartbeat. Digoxin can cause nausea, vomiting, and diarrhea. It may also cause some types of arrhythmias.
  • Sodium-glucose cotransporter-2 (SGLT-2) inhibitors: These medicines are often used to treat diabetes but can also help your heart work better. Possible side effects include kidney disease and infections.

Procedures and implanted devices: Your doctor may talk to you about a procedure or device if medicines don’t help improve your symptoms.

Alcohol septal ablation: This procedure shrinks the septum (the muscle dividing the left and right lower chambers of the heart). This may help your heart work better. It is used only to treat hypertrophic cardiomyopathy blood vessel that supplies blood to the thickened part of your heart. 

Septal myectomy: If your symptoms are serious, your doctor may have to remove part of your thickened septum to help your heart work better. This procedure is a type of heart surgery. It is used only to treat hypertrophic cardiomyopathy. You will be asleep during the procedure.

Catheter ablation: Catheter ablation is a procedure to stop abnormal electrical signals from moving through your heart and causing an irregular heartbeat.

Doctors perform catheter ablation in a hospital. Ablation is done through a procedure called cardiac catheterization that passes flexible tubes, or catheters, through your blood vessels until they reach your heart. Some catheters have wire electrodes that record and locate the source of your abnormal heartbeats. Other catheters can deliver treatments. Your doctor will aim the tip of a special catheter at the small area of heart tissue. A machine will send either radiofrequency (RF) waves, extremely cold temperatures, or laser light through the catheter tip to create a scar on the heart. The scar prevents abnormal electrical signals from causing irregular heartbeat.

Catheter ablation has some risks both during the procedure and during recovery, including:

  • Bleeding
  • Infection
  • Blood vessel damage
  • Heart damage
  • Arrhythmias
  • Blood clots

There also may be a very slight risk of cancer from radiation used during catheter ablation. Talk to your doctor and the technicians performing the ablation about whether you are or could be pregnant.

Surgically implanted devices: If your cardiomyopathy causes other heart conditions, like an irregular heartbeat or heart failure, you may need a left ventricular assist device, an implantable cardioverter defibrillator, or a pacemaker.

Heart transplant: You may need a heart transplant if you have life-threatening symptoms or complications of cardiomyopathy and all other treatments have not worked for you.

A heart transplant is surgery that removes a diseased heart and replaces it with a healthy heart from a deceased donor to improve your quality of life and increase your lifespan. Heart transplant surgery is a kind of open-heart surgery. It is done in a hospital under anesthesia.

After the surgery, you will recover in the hospital’s intensive care unit (ICU) and stay in the hospital for up to three weeks. During your recovery, you may start a cardiac rehabilitation program. Before leaving the hospital, you will learn how to keep track of your overall health; monitor your weight, blood pressure, pulse, and temperature; and learn the warning signs that your body may start rejecting your new heart. You will also learn to look out for early signs of an infection.

For the first three months after leaving the hospital, you will return often for tests to check for infection or rejection of your new heart, to see how well your heart is working, and to make sure that you are recovering well. You can help prevent complications after a heart transplant by practicing good hygiene, getting routine vaccines and dental care, and making healthy lifestyle choices.

Heart transplant has some serious risks.

  • Primary graft dysfunction may occur. This happens when the donor heart fails and cannot function. It is the most common cause of death in the first month after heart transplant.
  • Your immune system may reject your new heart. Rejection is most likely to occur within six months after the transplant. You will need to take medicines for the rest of your life to suppress your immune system and help prevent your body from rejecting your new heart. These medicines weaken your immune system and increase your chance for infection. Their long-term use also can increase your risk for cancer, cause diabetes and osteoporosis, and damage your kidneys.
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  • Cardiac allograft vasculopathy, a common and serious complication, may develop. This is an aggressive type of atherosclerosis, or build-up of plaque in the arteries, that over a few months or years can block the heart’s arteries and cause the donor heart to fail.

Over time, your new heart may fail due to the same reasons that caused your original heart to fail. Some patients who have a heart transplant that fails may be eligible for another transplant.

Despite these risks, heart transplant has a good success rate. Recent survival rates are about 85% at one year after surgery. Survival rates decrease by about 3% to 4% each extra year after surgery, mainly because of serious complications related to heart transplant.



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