A group of diseases that affect the heart muscle (the myocardium), cardiomyopathy is associated with abnormal muscle function or rhythms, and may also refer to abnormal thickening or dilation of the heart’s ventricles (lower chambers).
Many cardiomyopathies are influenced heavily by genetics, and some can actually lead to sudden death or heart failure-related disability.
Changes in your heart muscle
Cardiomyopathies all reflect a defect in the mechanics of the heart muscle or in its electrical system responsible for electrical rhythms that keep your heart beating. Usually there is thickening of the ventricles (hypertrophy) or an abnormal enlargement (dilatation). These changes result in difficulty pumping blood most effectively throughout the body and can lead to heart failure.
Traditionally, cardiomyopathies are grouped into three main categories, based on what is observed in and around the heart muscle:
- Dilated cardiomyopathies, in which the heart muscle becomes weak and the heart chambers enlarge;
- Hypertrophic cardiomyopathies, in which the heart muscle becomes thick, preventing blood from flowing from the heart;
- Restrictive cardiomyopathies, in which the heart muscle becomes abnormally stiff so that the chambers do not fill up properly.
More recently, experts began to categorize cardiomyopathies differently, according to genetic and non-genetic causes:
Primary cardiomyopathies, in which the disease mostly involves the heart muscle:
- Mixed (genetic and non-genetic causes)
- Acquired (infections, drug reactions, stress, for example)
Secondary cardiomyopathies, in which the disease involves many different organs, including the heart. Examples of secondary cardiomyopathies include those caused by diabetes and chronic thyroid disorders.
Identify symptoms of cardiomyopathy
Many patients have no symptoms at first. Some individuals may experience a sudden worsening of symptoms while others may see a worsening of symptoms develop slowly overtime. As cardiomyopathy progresses, symptoms of heart failure may become prevalent and can include:
- Feelings of breathlessness during activity or even at rest
- Swelling of the legs, ankles and feet
- Fluid build-up in the stomach that may cause bloating
- Abnormal heartbeats, including fluttering or pounding irregularities
- Fainting, dizzy spells or lightheadedness
Sudden cardiac death--as the first sign of inherited cardiomyopathy in young athletes--has led to an increased awareness of this medical condition.
Causes of cardiomyopathy
In many cases, the cause of a cardiomyopathy is unknown. In other cases, your doctor may be able to find a possible contributing factor to this condition. Other related causes of cardiomyopathy may include:
- Chronic, rapid heart rate
- Thyroid diseaseNutritional deficiency
- Long-term alcoholism
- Drug abuse
- Abuse of medications, such as tricyclic antidepressants
- Viral infections of the heart
- Side effect of chemotherapy drugs
- Genetic conditions
- Hemochromatosis (a build-up of iron in the heart)
- Autoimmune disorders (lupus and rheumatoid arthritis, for example)
What are your next steps?
In order to first diagnose cardiomyopathy, your doctor will likely begin with a complete medical history and assessment of your symptoms. If cardiomyopathy is suspected, your doctor may order a battery of diagnostic tests to confirm the diagnosis. These tests may include:
- X-ray of the chest
- Echocardiography, using sound waves to produce moving images of the heart
- Electrocardiography, which evaluates the electrical workings of the heart and identifies abnormalities in electrical impulses
- Cardiac catheterization, in which a catheter is threaded through the groin, arm or neck and into the heart to evaluate the arteries for blockage
- Myocardial biopsy, in which a sample is taken from the heart during cardiac catheterization to test for changes in cells of the heart muscle indicating cardiomyopathy
- Stress test
- MRI of the heart
- Blood tests
Treatment of cardiomyopathy may not be necessary if there are no symptoms present. The goal of treatment is to control and suppress the symptoms. Treatment will be dependent upon the type of cardiomyopathy and the severity of symptoms. Your next steps might also include:
- Medications to manage heart failure (ACE inhibitors, beta blockers)
- Anti-arrhythmics, to help prevent arrhythmias
- Blood thinners to prevent clots
- Corticosteroids, in certain cases, to reduce inflammation
- Open heart surgery to repair thickening and encourage blood flow (when medications are not controlling symptoms adequately)
- Heart transplant for end-stage heart failure
- Non-surgical alcohol septal ablation (ASS), in which alcohol is injected through a small tube into the small artery that supplies blood to the thickened portion of the heart. The alcohol kills a select area of cells to minimize the thickened portion.
- Surgically implanted devices
Lifestyle changes can also help
In some cases, it may be possible to manage cardiomyopathy by taking better care of your heart and muscles, and by making heart-healthy changes:
- Follow a heart-healthy diet that is low in sodium
- Maintain a healthy body weight
- Lose excess body fat
- Quit smoking
- Limit alcohol intake
- Avoid drug abuse
- Get an adequate amount of sleep
- Manage and reduce stress
- Exercise, after consulting your doctor and evaluating physical activity
- Manage any underlying medical conditions
In many cases, cardiomyopathy cannot be prevented. It is important to make your healthcare practitioner aware of your medical and family history in order to manage any underlying conditions that may contribute to the onset of cardiomyopathy.
If you have been diagnosed with cardiomyopathy, it is essential to remain under a doctor’s care. If you are experiencing any new or worrisome symptoms, report them immediately. New symptoms may be an indication that your condition is worsening.
Cardiomyopathy can lead to heart failure over time. If you suspect you may have cardiomyopathy, contact your doctor immediately.