Cardiomyopathy, or heart muscle disease, is a type of progressive heart disease in which the heart is abnormally enlarged, thickened, and/or stiffened. As a result, the heart muscle's ability to pump blood is weakened, often causing heart failure and the backup of blood into the lungs or rest of the body. The disease can also cause abnormal heart rhythms.
There are three main types of cardiomyopathy:
- Dilated cardiomyopathy
- Hypertrophic cardiomyopathy
- Restrictive cardiomyopathy
What is a Dilated Cardiomyopathy?
Dilated cardiomyopathy (DCM) is a condition in which the heart's ability to pump blood is decreased because the heart's main pumping chamber, the left ventricle, is enlarged and weakened. In some cases, it prevents the heart from relaxing and filling with blood as it should. Over time, it can affect the other heart chambers.
What Are the Symptoms of DCM?
Many people with dilated cardiomyopathy have no symptoms or only minor symptoms, and live a normal life. Other people develop symptoms, which may progress and worsen as heart function worsens.
Symptoms of DCM can occur at any age and may include:
- Heart failure symptoms (shortness of breath and fatigue).
- Swelling of the lower extremities.
- Fatigue (feeling overly tired).
- Weight gain.
- Fainting (caused by conditions such as irregular heart rhythms, abnormal responses of the blood vessels during exercise, or no cause may be found).
- Palpitations (fluttering in the chest due to abnormal heart rhythms).
- Dizziness or lightheadedness.
- Blood clots can form in the dilated left ventricle as a result of pooling of the blood. If a blood clot breaks off, it can lodge in an artery and disrupt blood flow to the brain, causing
- stroke. A clot can also block blood flow to the organs in the abdomen or legs.
- Chest pain or pressure.
- Sudden death.
What Causes DCM?
DCM can be inherited, but it is primarily caused by a variety of other factors, including:
Severe coronary artery disease
- Thyroid disease
- Viral infections of the heart
- Heart valve abnormalities
- Drugs that are toxic (or cause damage) to the heart
- It can also occur in women after childbirth (postpartum cardiomyopathy).
How Is DCM Diagnosed?
DCM is diagnosed based on medical history (your symptoms and family history), physical exam, blood tests, electrocardiogram (ECG or EKG), chest X-ray, echocardiogram, exercise stress test, cardiac catheterization, CT scan, and MRI.
Another test rarely done to determine the cause of a cardiomyopathy is a myocardial biopsy, or heart biopsy, where a tissue sample is taken from the heart and examined under a microscope to determine the cause of the symptoms.
If you have a relative with dilated cardiomyopathy, ask your doctor if you should be screened for the condition. Genetic testing may also be available to identify abnormal genes.
What Is Hypertrophic Cardiomyopathy?
Hypertrophic cardiomyopathy (HCM) is associated with thickening of the heart muscle, most commonly at the septum between the ventricles, below the aortic valve. This leads to stiffening of the walls of the heart and abnormal aortic and mitral heart valve function, both of which may impede normal blood flow out of the heart.
What Are the Symptoms of Hypertrophic Cardiomyopathy?
Many people with HCM have no symptoms or only minor symptoms, and live a normal life. Other people develop symptoms, which progress and worsen as heart function worsens.
Symptoms of HCM can occur at any age and may include:
- Chest pain or pressure (occurs usually with exercise or physical activity, but can also occur with rest or after meals)
- Shortness of breath (dyspnea), especially with exertion
- Fatigue (feeling overly tired)
- Fainting (caused by irregular heart rhythms, abnormal responses of the blood vessels during exercise, or no cause may be found)
- Palpitations (fluttering in the chest) due to abnormal heart rhythms (arrhythmias), such as atrial fibrillation or ventricular tachycardia
- Sudden death (occurs in a small number of patients with HCM)
What Causes Hypertrophic Cardiomyopathy?
HCM can run in families, but the condition may also be acquired as a part of aging or high blood pressure. In other instances, the cause is unknown.
How Is Hypertrophic Cardiomyopathy Diagnosed?
HCM is diagnosed based on medical history (your symptoms and family history), a physical exam, and echocardiogram results. Additional tests may include blood tests, electrocardiogram, chest X-ray, exercise stress test, cardiac catheterization, CT scan, and MRI.
How Is Hypertrophic Cardiomyopathy Treated?
Treatment of HCM depends on whether there is narrowing in the path that blood takes to leave the heart (called the outflow tract); how the heart is functioning; and if arrhythmias are present. Treatment is aimed at preventing symptoms and complications and includes risk identification and regular follow-up, lifestyle changes, medications, and procedures as needed.
What Lifestyle Changes Are Recommended to Treat Hypertrophic Cardiomyopathy?
- Diet. Drinking at least six to eight, 8-ounce glasses of water a day is important, unless fluids are restricted. In hot weather, you should increase your fluid intake. Fluid and salt restrictions may be necessary for some patients if heart failure symptoms are present. Ask your doctor about specific fluid and dietary guidelines, including information about alcoholic beverages and caffeinated products.
- Exercise. Your doctor will tell you if you may exercise or not. Most people with cardiomyopathy are able to do non-competitive aerobic exercise. However, your doctor may ask you not to exercise, based on your symptoms and the severity of your disease. Heavy weight lifting is not recommended.
- Regular follow-up visits. Patients with HCM should have an annual follow-up visit with their cardiologist to monitor their condition. Follow-up appointments may be more frequent when HCM is first diagnosed.
What Is Restrictive Cardiomyopathy?
Restrictive cardiomyopathy, the rarest form of cardiomyopathy, is a condition in which the walls of the lower chambers of the heart (the ventricles) are abnormally rigid and lack the flexibility to expand as the ventricles fill with blood.
The pumping or systolic function of the ventricle may be normal but the diastolic function (the ability of the heart to fill with blood) is abnormal. Therefore, it is harder for the ventricles to fill with blood, and with time, the heart loses the ability to pump blood properly, leading to heart failure.
What Are the Symptoms of Restrictive Cardiomyopathy?
Many people with restrictive cardiomyopathy have no symptoms or only minor symptoms, and live a normal life. Other people develop symptoms, which progress and worsen as heart function worsens.
Symptoms of restrictive cardiomyopathy can occur at any age and may include:
- Shortness of breath (at first with exercise; but over time it occurs at rest)
- Fatigue (feeling overly tired)
- Inability to exercise
- Swelling of the legs and feet
- Weight gain
- Nausea, bloating, and poor appetite (related to fluid retention)
- Palpitations (fluttering in the chest due to abnormal heart rhythms)
- Less common symptoms of restrictive cardiomyopathy:
- Fainting (usually caused by irregular heart rhythms or abnormal responses of the blood vessels during exercise)
- Chest pain or pressure (occurs usually with exercise or physical activity but can also occur with rest or after meals)
What Causes Restrictive Cardiomyopathy?
Restrictive cardiomyopathy is not usually inherited and its cause is often unknown. Known causes of restrictive cardiomyopathy may include:
- Buildup of scar tissue (often for no known reason)
- Buildup of abnormal proteins (amyloidosis) in the heart muscle
- Chemotherapy or chest exposure to radiation
- Excess iron (hemochromatosis) in the heart
- Other systemic diseases (e.g. (sarcoidosis)
How Is Restrictive Cardiomyopathy Diagnosed?
The size of the heart may remain normal with restrictive cardiomyopathy. In some cases, restrictive cardiomyopathy may be confused with constrictive pericarditis, a condition in which the layers of the pericardium (the sac that surrounds the heart) become thickened, calcified, and stiff.
Restrictive cardiomyopathy is diagnosed based on medical history (your symptoms and family history), physical exam, and tests: such as blood tests, electrocardiogram, chest X-ray, echocardiogram, exercise stress test, cardiac catheterization, CT scan, and MRI.
A myocardial biopsy, or biopsy of the heart muscle, occasionally is done to determine the cause of cardiomyopathy. During a myocardial biopsy, a small tissue sample is taken from the heart and examined under a microscope to examine the cause of the symptoms.
What Is the Treatment for Restrictive Cardiomyopathy?
Treatment of restrictive cardiomyopathy is difficult. Treatment is usually focused on treating the cause of this condition. Doctors recommend lifestyle changes and medications to treat heart failure