Cardiomyopathy is a disease of the heart muscle. The name comes from the roots “cardio” meaning heart, “myo” meaning muscle and “pathy” meaning disease. The known causes of cardiomyopathy are many, and include coronary artery disease and valvular heart disease.
Cardiomyopathy occurs in three major types, all of which affect your heart’s ability to pump blood and deliver it to the rest of your body. Treatment of cardiomyopathy depends on which type you have and may include medications, implantable devices or, in severe cases, a heart transplant.
Some people who develop cardiomyopathy may have no signs and symptoms in the early stages of the disease. But as the condition advances, signs and symptoms usually appear. These signs and symptoms are those most commonly associated with the syndrome called congestive heart failure.
They may include:
- Breathlessness with exertion or even at rest
- Swelling of the lower extremities
- Distention of the abdomen with fluid
- Irregular heart rhythm
- Dizziness, lightheadedness and fainting
No matter what type of cardiomyopathy you have, signs and symptoms tend to progress over time unless treated. In certain people, this deterioration accelerates rapidly, while in others, the disease may reach a plateau and stabilize for a long period of time. In some cases of dilated cardiomyopathy, the most common of the three major types, the disease may improve on its own completely.
The causes of the common forms of cardiomyopathy include:
- Dilated cardiomyopathy. This is the most common form of cardiomyopathy. In this disorder, the left ventricle — your heart’s main pumping chamber — becomes enlarged (dilated) and its pumping ability becomes less forceful. Although this type can affect people of all ages, it occurs most often in middle-aged people, with an incidence greater among men than women. Some people with dilated cardiomyopathy may have inherited the condition.
- Hypertrophic cardiomyopathy. This type involves abnormal growth or thickening of your heart muscle, particularly affecting the muscle of the left ventricle. As thickening occurs, the heart tends to stiffen and the size of the pumping chamber may shrink, interfering with your heart’s ability to deliver blood to your body. Hypertrophic cardiomyopathy can develop at any age, but the condition tends to be more severe among those diagnosed during childhood. Researchers have identified abnormal genes that predispose people to hypertrophic cardiomyopathy. Most affected people have a family history of the disease.
- Restrictive cardiomyopathy. The heart muscle in people with restrictive cardiomyopathy becomes rigid and less elastic, interfering with the expansion and filling of the heart’s ventricles with blood between heartbeats or contractions. While restrictive cardiomyopathy can occur at any age, it tends to affect older people most often. It’s much less common than the other types of cardiomyopathy. Restrictive cardiomyopathy can occur for no known reason(idiopathic) or may result from diseases elsewhere in the body that affect the heart. One example is amyloidosis, a rare condition in which abnormal proteins present in the blood are deposited into the heart.
In most people, the cause of cardiomyopathy is unknown. In some people, however, doctors are able to identify a cause or contributing factors, including some that affect the heart and cardiovascular system. For example, any of the following conditions may cause or contribute to a dilated and poorly functioning heart:
- Sustained high blood pressure
- Heart valve problems
- Heart tissue damage from a previous heart attack
- Chronic rapid heart rate
- Metabolic disorders, such as thyroid disease or diabetes
- Nutritional deficiencies of essential vitamins and minerals, such as thiamin (vitamin B-1), selenium, calcium and magnesium
- Excessive use of alcohol over many years
- Abuse of cocaine or antidepressant medications, such as tricyclic antidepressants
- Use of some chemotherapy drugs to treat cancer
- Certain viral infections, which may injure the heart and trigger cardiomyopathy
Hemochromatosis is a disorder in which your body doesn’t properly metabolize iron, causing the accumulation of iron in your heart muscle. This can lead to a weakening of the heart muscle, resulting in the appearance of dilated cardiomyopathy.
How it is Diagnosed:
Your doctor will conduct a physical examination and take a medical history, including asking about your family history of heart problems. He or she will also ask about the circumstances in which your symptoms occur — for example, whether physical activity brings on your symptoms. If your doctor suspects cardiomyopathy, you may need to undergo several tests to confirm the diagnosis and rule out other conditions. These tests may include:
- Chest X-ray. An image of your heart will show whether it’s enlarged.
- Echocardiogram. By using sound waves or ultrasound to noninvasively create images of your heart, your doctor can view the size of your heart and its motions as it beats.
- Electrocardiogram (ECG). In this noninvasive test, electrode patches are attached to your skin to measure electrical impulses from your heart. An ECG can show disturbances in the electrical activity of your heart, which may identify abnormal heart rhythms and areas of injury.
- Cardiac catheterization and biopsy. In this procedure, a thin tube (catheter) is threaded through your blood vessels and into your heart, where a small sample (biopsy) of your heart can be extracted for analysis in the laboratory. Pressure within the chambers of your heart can be measured. Pictures of the arteries of the heart can be taken (coronary angiogram) to ensure that you do not have any blockage.
- Blood tests. One blood test can measure brain natriuretic peptide (BNP), a protein produced in your heart. Your blood level of BNP rises when your heart is subjected to the stress of congestive heart failure. Measuring your BNP level helps your doctor differentiate congestive heart failure from other disorders such as lung disease.
Another blood test measures your iron level. Having too much may indicate an iron overload disorder called hemochromatosis. Accumulating too much iron in your heart muscle can weaken it. Early diagnosis and treatment can prevent the progression of this serious disease. Thyroid problems that can affect the heart also can be detected by a simple blood test.
The overall goals of treatment for cardiomyopathy are to:
- Manage your symptoms
- Prevent progression of your illness
- Reduce your risk of complications
Your doctor may recommend adopting the following lifestyle changes to help you manage cardiomyopathy:
- Quit smoking
- Lose excess weight
- Adopt a low-salt diet
- Get modest exercise, after discussing with your doctor the most appropriate program of physical activity
- Abstain from drinking alcohol
Treatment varies by which of the major types of cardiomyopathy you have:
- Dilated cardiomyopathy. Doctors often prescribe medications for dilated cardiomyopathy. Angiotensin-converting enzyme (ACE) inhibitors — such as enalapril (Vasotec), lisinopril (Zestril, Prinivil), ramipril (Altace) or captopril (Capoten) — can improve the heart’s pumping capability. Diuretics, such as furosemide (Lasix), can reduce fluid retention. Beta blockers — such as atenolol (Tenormin), carvedilol (Coreg) and metoprolol (Lopressor, Toprol XL) — can improve cardiac function and reduce the risk of death in people with dilated cardiomyopathy.
Another option for some people with abnormal electrocardiograms is a special pacemaker that coordinates the contractions between the left and right ventricle (biventricular pacing). In people who may be at risk of serious arrhythmias, drug therapy or an implantable cardioverter-defibrillator (ICD) may be options. ICDs are small, minicassette-sized devices implanted in your chest to continuously monitor your heart rhythm and deliver precisely calibrated electrical shocks when needed to control abnormal, rapid heartbeats. The devices can also work as pacemakers.
- Hypertrophic cardiomyopathy. Your doctor may recommend beta blockers such as Lopressor or calcium channel blockers such as verapamil (Calan, Isoptin), which can relax your heart, slow its pumping action and stabilize heart rhyhm. tFor some people, a pacemaker or an ICD may be recommended. In advanced cases of hypertrophic cardiomyopathy, a surgeon may remove a portion of the thickened muscle wall that interferes with normal blood flow. This procedure, called septal myotomy-myectomy, can reduce symptoms in most cases.
Your doctor also may recommend a new therapy called alcohol ablation. This nonsurgical procedure, which uses injected alcohol to destroy extra heart muscle, may reduce thickening and improve blood flow.
- Restrictive cardiomyopathy. As with all forms of cardiomyopathy, your doctor will recommend you pay careful attention to your salt and water intake and monitor your weight daily. Treatment of fluid retention is with diuretics. You may be prescribed medications to lower your blood pressure and control fast or irregular heart rhythms.
Many of the medications that doctors prescribe for cardiomyopathy may have side effects. Be sure to discuss these possible side effects with your doctor before taking any of these drugs.
Having cardiomyopathy may produce the following complications:
- Blood clots. Any of the types of cardiomyopathy may make you more susceptible to forming blood clots in your heart. If clots are pumped out of the heart and enter your circulatory system, they can obstruct the blood vessels and blood flow to vital organs, including your heart and brain. If clots develop on the right side of your heart, they may travel to your lungs. To reduce your risk, your doctor may prescribe a blood thinner (anticoagulant medication).
- Heart murmur. Because people with dilated cardiomyopathy have an enlarged heart, two of the heart’s four valves — the mitral and tricuspid valves — may not close properly, often leading to the backflow of blood. This flow creates audible sounds or heart murmurs.
- Cardiac arrest. All forms of cardiomyopathy can lead to abnormal heart rhythms. Some of these heart rhythms are too slow to sustain the circulation and some are too fast to allow the heart to beat efficiently. In either case, these abnormal heart rhythms can result in fainting or, in some cases, sudden death from a complete cessation of heart beating called cardiac arrest.