Cardiomyopathy is an umbrella term for a variety of conditions of the heart muscle. (1) When you have cardiomyopathy, the muscle in the heart thickens, stiffens, thins out, or fills up with substances that shouldn’t be there. This reduces the heart muscle’s ability to pump blood, which can cause the backup of blood into the lungs or the rest of the body (aka heart failure) and can lead to abnormal heartbeats (arrhythmia).
Signs and Symptoms of Cardiomyopathy
Some people who have cardiomyopathy never have symptoms. Others may not show signs early on, but do have symptoms later in the course of the disease. Signs and symptoms of cardiomyopathy include: (1,2)
- Shortness of breath or trouble breathing
- Swelling in the ankles, feet, legs, abdomen, and veins in the neck
- Arrhythmias or palpitations
- Syncope (fainting or briefly passing out)
- Fainting during physical activity
- Chest pain, especially after physical exertion or heavy meals
- Heart murmurs (unusual sounds associated with heartbeats)
- Heart failure (typically in the later stages of cardiomyopathy)
Causes and Risk Factors of Cardiomyopathy
The cause of cardiomyopathy is often unknown, especially when it occurs in children. (3) However, various diseases or conditions can lead to cardiomyopathy. These include: (1)
- A family history of cardiomyopathy, heart failure, or sudden cardiac arrest
- Connective tissue disease and other types of autoimmune disease
- Coronary artery disease or a heart attack
- Diseases that can damage the heart, such as hemochromatosis, sarcoidosis, or amyloidosis
- Endocrine diseases, including thyroid conditions and diabetes
- Infections in the heart muscle
- Long-term alcoholism or cocaine abuse
- Muscle conditions such as muscular dystrophy
- Pregnancy-related issues
Types of Cardiomyopathy
There are five main types of cardiomyopathy: (3)
Dilated Cardiomyopathy Dilated cardiomyopathy (DCM) is the most common type of cardiomyopathy. (4) It affects the heart’s ventricles (lower, pumping chambers) but can also affect the atria (upper chambers).
The disease often originates in the left ventricle. The heart muscle begins to dilate (stretch and become thinner), and the inside of the chamber becomes larger. Then the condition commonly affects the right ventricle and in many cases the atria. As a result, the heart muscle doesn’t contract the way it’s supposed to, and it can’t pump blood very well. This can lead to heart failure, heart valve problems, arrhythmias, and blood clots in the heart.
Dilated cardiomyopathy mostly affects adults ages 20 to 60.
The cause of dilated cardiomyopathy is often unknown, but up to one-third of the people who have it have a genetic form that is inherited from a parent. DCM can also be caused by coronary heart disease (heart attack), high blood pressure (hypertension), diabetes, thyroid disease, viral hepatitis, HIV, infections (especially viral infections that cause inflammation in the heart muscle), alcohol (especially if you also have an unhealthy diet), complications during the last month of pregnancy or within five months of birth, toxins (such as cobalt), certain drugs (such as cocaine and amphetamines), and certain medicines used to treat cancer like doxorubicin (Adriamycin) and daunorubicin (Cerubidine).
Hypertrophic Cardiomyopathy Hypertrophic cardiomyopathy (HCM) is usually caused by abnormal genes involved in the development of heart muscle. (5) As a result of these abnormal genes, the walls of the left ventricle contract harder and become abnormally thick and stiff, which leads to less blood being taken in and pumped out to the body with each heartbeat.
There are two types of hypertrophic cardiomyopathy: obstructive and nonobstructive. In obstructive HCM, the wall between the two bottom chambers of the heart gets thicker. The walls of the pumping chamber can also become stiff, which may block or reduce the blood flow from the left ventricle to the aorta. This is the most common form of HCM.
In nonobstructive HCM, the left ventricle becomes thickened and stiff, which limits how much blood it can take in and pump out, but blood flow is not blocked.
HCM is usually inherited from parents, and it’s one of the most common forms of genetic heart disease. The disease has been cited as the most common reason for sudden cardiac death in young people and athletes under the age of 35. However, it can happen at any age, and most people are diagnosed in middle age.
Arrhythmogenic Right Ventricular Dysplasia (ARVD) With this rare form of cardiomyopathy, fat and scar tissue develop within the muscle in the right ventricle and less commonly in the left ventricle. (6) This degeneration is worsened by physical exercise and disrupts the heart’s electrical signals, causing life-threatening arrhythmias.
ARVD usually occurs in teens and young adults and can cause sudden cardiac arrest in young athletes. The disease is also referred to as arrhythmogenic right ventricular cardiomyopathy, right ventricular cardiomyopathy, or right ventricular dysplasia. Scientists believe that ARVD is an inherited disease.
Restrictive Cardiomyopathy (RCM) Restrictive cardiomyopathy is a rare form of cardiomyopathy. (1) The disease occurs when the heart’s ventricles stiffen because abnormal tissue, such as scar tissue, has replaced the normal heart muscle. (7) As a result, the ventricles can’t relax normally and fill with blood, and the upper heart chambers become enlarged. Over time, blood flow in the heart is reduced, which can lead to heart failure or arrhythmias.
Restrictive cardiomyopathy most commonly affects older adults. It is least common in children, affecting less than 1 per 1,000,000 children. (7) The cause of restrictive cardiomyopathy is unknown in most cases, but genetic factors are thought to play a role in some forms.
Transthyretin Amyloid Cardiomyopathy (ATTR-CM) ATTR-CM is characterized by deposits of transthyretin amyloid fibrils in the walls of the left ventricle of the heart. (9) When the transport protein transthyretin doesn’t assemble normally, the abnormal proteins become amyloid fibrils, which travel through the bloodstream. Deposits of amyloid fibrils in the heart cause the heart walls to become stiff, which prevents the left ventricle from properly relaxing and filling with blood. The stiffening also limits the left ventricle’s ability to pump enough blood out of the heart.
There are two types of ATTR-CM: hereditary and wild type. With the hereditary type, a mutation in the transthyretin gene leads to the amyloid deposits. For those with a family history of this cardiomyopathy, effects of the illness can start as early as age 20 or as late as age 80. In the United States, the most common mutation is found in Black Americans and in older patients who may be misdiagnosed with high blood pressure-related heart disease.
Wild-type ATTR-CM doesn’t occur through a genetic mutation. It usually affects the heart and can be associated with carpal tunnel syndrome and peripheral neuropathy (pain and numbness in the hands and feet). People with wild-type ATTR-CM typically begin to experience symptoms after age 65.
The condition is likely underdiagnosed. Some patients may have no symptoms or mild symptoms, and others may wind up with end-stage heart failure. In its early stages, ATTR-CM may be mistaken for other conditions, such as heart failure related to high blood pressure and hypertrophic cardiomyopathy.
Wild-type ATTR-CM is found mostly in men; the average age at diagnosis is 75. (10)
How Is Cardiomyopathy Diagnosed?
Knowing if you’re at high risk for cardiomyopathy is important because you have a better chance of diagnosing it early, when treatment may be most effective. (2)
To diagnose cardiomyopathy, your doctor will inquire about your medical history, as well as any symptoms you may have. They will also want to know whether any of your family members have been diagnosed with cardiomyopathy, heart failure, or cardiac arrest.
Your doctor will also conduct a physical exam, where they listen to your heart and lungs for sounds that may suggest cardiomyopathy and look for other signs of the disease.
They may also recommend certain tests to diagnose cardiomyopathy, including:
- Blood tests
- A chest X-ray to show whether your heart is enlarged and whether fluid is building up in your lungs
- An electrocardiogram (EKG or ECG), which shows how fast your heart is beating and whether its rhythm is steady or irregular
- Holter and event monitors, which are portable devices that record your heart’s electrical activity
- An echocardiogram (echo), a test that uses sound waves to create a moving picture of your heart
- A stress test, in which you walk in place on an inclined treadmill to make your heart work hard while tests are performed (or you may be given medicine to simulate the effects of exertion)
To evaluate the cause of cardiomyopathy, the following diagnostic procedures may be performed:
- Cardiac Catheterization In cardiac catheterization, your healthcare provider inserts a catheter through a blood vessel and threads it to the heart. Then they use X-ray imaging to check the pressure and blood flow in your heart’s chambers.
- Coronary Angiography In this procedure, which is often done during cardiac catheterization, dye is injected into your coronary arteries. This allows your doctor to analyze blood flow within your heart and blood vessels.
- Myocardial Biopsy In a myocardial biopsy, your doctor removes a piece of your heart muscle, then studies it to see whether changes in cells have taken place.
- Genetic Testing Your doctor may recommend genetic testing to look for signs of cardiomyopathy in family members. Your doctor may also suggest genetic testing if they suspect that you may have cardiomyopathy but you haven’t shown any signs or symptoms.
Prognosis of Cardiomyopathy
For some people, signs and symptoms of cardiomyopathy tend to get worse without treatment. (11) In some cases, the disease worsens quickly. Other people may have no symptoms or mild symptoms for a long time before the condition worsens. In serious cases, cardiomyopathy is a major cause of heart failure and one of the most common conditions leading to heart transplantation. (12)
However, some people who have cardiomyopathy but do not show any signs or symptoms may not need any treatment. (13) In fact, dilated cardiomyopathy that comes on suddenly may improve on its own in some cases.
Treatment and Medication Options for Cardiomyopathy
The purpose of cardiomyopathy treatment is to slow down the course of the disease, control symptoms, and prevent sudden death. (1) Treatment depends on which type of cardiomyopathy you have. Your doctor may also treat you for the conditions that led to cardiomyopathy or recommend surgery.
Your doctor may prescribe different medications depending on the type of cardiomyopathy that you have. Medications may be prescribed for the following reasons: (13)
- To Lower Your Blood Pressure ACE inhibitors, angiotensin 2 receptor blockers, beta-blockers, and calcium channel blockers can all be used to reduce blood pressure.
- To Slow Your Heart Rate Beta-blockers, calcium channel blockers, and digoxin (Lanoxin) can all be used to slow your heart rate if rapid heart rate is a contributing factor to your cardiomyopathy.
- To Keep Your Heart Beating With a Normal Rhythm Drugs called antiarrhythmics help prevent arrhythmias.
- To Remove Excess Fluid and Sodium From Your Body Diuretics, or “water pills,” can be used to help remove excess fluid and sodium from your body.
- To Prevent Blood Clots Anticoagulants, or blood thinners, help to prevent blood clots from forming.
- To Reduce Inflammation Corticosteroids can be used in some forms of cardiomyopathy related to autoimmune diseases.
- To Improve Symptoms of Obstructive Hypertrophic Cardiomyopathy Mavacamten (Camzyos) is the first cardiac myosin inhibitor that has been approved for use in the U.S. to treat a genetic form of cardiomyopathy.
Surgically Implanted Devices
Your doctor may also suggest devices that can be surgically implanted in the heart to offer protection from life-threatening arrhythmias, improve heart function, and relieve symptoms of cardiomyopathy. These devices include: (11)
- Implantable Cardioverter-Defibrillator (ICD) This device monitors your heart rhythm and delivers electric shocks to control abnormal heart rhythms.
- Ventricular Assist Device (VAD) This helps blood circulate through your heart.
- Pacemaker This device is placed under the skin in the chest or abdomen and uses electrical impulses to control arrhythmias.
Nonsurgical, catheter-based procedures for cardiomyopathy include:
- Septal Ablation A small part of the thickened heart muscle is destroyed by injecting alcohol through a catheter into the artery supplying blood to that area, which allows blood to flow.
- Radiofrequency Ablation Your healthcare provider guides catheters through your blood vessels to your heart to treat abnormal heart rhythms with electrodes.
Your doctor may also recommend different types of surgery to treat cardiomyopathy. These include:
- Septal Myectomy An open-heart surgery in which a surgeon removes part of the thickened heart muscle wall that separates the two bottom heart chambers, which improves blood flow through the heart.
- Heart Transplant A heart transplant might be recommended if you have end-stage heart failure and medications and other treatments are no longer effective.
Alternative and Complementary Therapies
In addition to taking medication and other forms of treatment, your doctor may suggest that you change your diet, improve physical activity, reduce stress, and avoid alcohol and other drugs. (1)
Prevention of Cardiomyopathy
In many cases, you can’t prevent cardiomyopathy, especially if the disease is genetic. (11) However, you can help reduce your chance of developing cardiomyopathy by making heart-healthy lifestyle choices, including:
- Avoiding the use of alcohol and cocaine
- Controlling high blood pressure, high cholesterol, and diabetes
- Eating a healthy diet
- Getting regular exercise
- Getting adequate sleep
- Reducing stress
Complications of Cardiomyopathy
Cardiomyopathy can lead to other heart conditions. These include: (11)
- Heart Failure When you have heart failure, your heart can’t pump adequate blood for your body, which can be life-threatening if not treated.
- Blood Clots Blood clots may form in your heart when your heart can’t pump blood as well as it should. If clots enter your bloodstream, they can impede blood flow to your other organs, including your heart and brain.
- Valve Problems As cardiomyopathy causes the heart to get bigger, the heart valves might not close properly. This can lead to a backward flow of blood.
- Cardiac Arrest and Sudden Death Cardiomyopathy can cause abnormal heart rhythms, which can cause fainting or, in some cases, sudden death.
Research and Statistics: Who Has Cardiomyopathy?
Cardiomyopathy does not discriminate in terms of age, gender, or race, although dilated cardiomyopathy is more common in Black people than in white people, and in males than in females. (1) The condition often goes undiagnosed and some people do not show any symptoms, especially in the early stages of the disease, so it’s difficult to get an exact number of people living with it. But according to the U.S. Centers for Disease Control and Prevention, as many as 1 in 500 adults may have cardiomyopathy. (1)
Related Conditions and Causes of Cardiomyopathy
Believe it or not, an actual broken heart can lead to a type of cardiomyopathy. (14)
Broken heart syndrome, also called stress-induced cardiomyopathy or takotsubo cardiomyopathy, can happen as a result of an emotionally stressful event, such as a divorce or the death of a loved one, or even due to the shock of good news (like winning the lottery).
In broken heart syndrome, a part of your heart temporarily enlarges and doesn’t pump efficiently, while the rest of your heart functions normally or with even more powerful contractions. It’s characterized by sudden, intense chest pain, which is a reaction to a surge of stress hormones.
Broken heart syndrome is more likely to happen to women than to men. It may be misdiagnosed as a heart attack, but stress-induced cardiomyopathy can happen to healthy people, and unlike a heart attack, there’s no evidence of blocked heart arteries.
Broken heart syndrome is usually treatable, and most people make a full recovery within weeks, but in some cases, it can be fatal.
Pediatric cardiomyopathy, or cardiomyopathy in children, is another type of cardiomyopathy. (1) It can be secondary to a congenital abnormality, genetically inherited from family, or acquired through a viral infection. Sometimes, the cause is unknown. It is a common cause of sudden cardiac arrest in young people. Early detection and intervention can be beneficial for children with cardiomyopathy.
Resources We Love
The American Heart Association is the oldest and largest voluntary organization in America dedicated to fighting heart disease and stroke. The website offers information on heart-related topics such as cardiomyopathy, cardiac arrest, and heart failure, as well as heart-healthy lifestyle tips.
CDC is the nation’s health protection agency and one of the major operating components of the Department of Health and Human Services. The CDC offers information on the types of cardiomyopathy, as well as causes, symptoms, treatment, and prevention.
The Mayo Clinic is a nonprofit organization that focuses on clinical practice, education, and research. It offers information on the symptoms, causes, risk factors, and complications of cardiomyopathy.