Cardiomyopathy

Cardiomyopathy is any abnormality in the structure or workings of the middle muscular layer of the heart wall in the lower chambers (the ventricles) of the heart, with the exception of:

  • Birth defects
  • Diseases of the blood vessels
  • Diseases of the heart's valves
  • Isolated diseases of the heart's electrical system and nodes or the membrane that encloses the heart

Symptoms

Signs that cardiomyopathy may be present include:

  • Rattling sounds in lower part of the chest during breathing
  • Difficulty breathing
  • Fatigue
  • Fever, if the cardiomyopathy is caused by a virus or bacteria
  • Swollen neck veins
  • Normal or low blood pressure
  • Swelling of the hands and feet that has a pitted surface to the skin
  • Abnormally rapid heart rate
In severe cases, the liver may be swollen, fluid may collect in abdomen around the organs and there may be a loss of muscle. It may be possible to hear blood flowing backwards through the valves of the heart (mitral valve regurgitation or tricuspid valve regurgitation), which causes murmuring sounds.

Blood clots can form on the walls of any chamber of the heart once the chamber has stretched out significantly. Irregular heartbeats (arrhythmias) can become a complication of cardiomyopathy in its late stages.

Causes and Risk Factors

Cardiomyopathy can be caused by several factors:

  • Coronary artery disease
  • Virus infections
  • Alcohol abuse combined with poor nutrition
  • Beriberi, a condition in which the body doesn't get or can¿t process thiamine, a B vitamin.
In some cases, it is not possible to identify a cause. This is known as primary or idiopathic cardiomyopathy.

Diagnosis

A doctor will take your medical history and do a physical examination. He or she will try to rule out other causes that have similar symptoms such as high blood pressure, diseases of the heart valves or a heart attack.

He or she might order:

    Treatment

    Cardiomyopathy is a serious condition that tends to grow worse and become life threatening. If an underlying cause can be found - such as alcoholism or beriberi - that can be treated. Usually, however, treatment is limited to addressing symptoms such as heart failure and improving the effectiveness of the heart's ability to pump.

    Certain drugs can be helpful, including     ACE inhibitors, calcium-channel blockers, beta blockers and diuretics to reduce fluid retention. Drugs that control the clotting of the blood such as warfarin maybe prescribed to prevent clots that might break off and block a blood vessel.

    Getting enough rest and avoiding stress are important. Physical exercise to the degree that the symptoms permit it can be helpful in improving your overall well being.

    Because cardiomyopathy is a life-threatening condition, persons with this condition represent the greatest proportion of people who receive transplants. Several types of     ventricular assist devices can be used to keep a patient alive while waiting for heart transplant surgery.

    Dilated cardiomyopathy

    Several types of heart muscle disorders can cause the lower chambers of the heart (the ventricles) to become enlarged and unable to pump enough blood for the body's needs. This condition is called dilated (congestive) cardiomyopathy and frequently leads to heart failure.

    Causes and Risk Factors

    In the United States, the most common cause of dilated cardiomyopathy is extensive coronary artery disease. When coronary artery disease blocks the arteries that bring blood to the heart muscle, the muscle can become damaged or even die because it isn't receiving enough blood. Scar tissue replaces the dead heart muscle. The heart muscle is no longer able pump strongly enough. The remaining, healthy heart muscle stretches and becomes thicker (hypertrophies) to make up for the lost ability to pump. Eventually, however, heart failure develops.

    Dilated cardiomyopathy may also be caused by     myocarditis, a viral infection that causes serious swelling and tenderness in the heart muscle. In this case, the condition is called viral cardiomyopathy. The virus weakens the heart muscle. The muscle stretches and thickens in an effort to pump more effectively. This leads to dilated cardiomyopathy and eventually heart failure. Bacterial infections of the heart muscle can also cause dilated cardiomyopathy.

    Other causes include:

    • Chronic hormone disorders such as diabetes or thyroid disease that has been poorly controlled for a long time
    • Heavy drinking, especially if nutrition is also poor
    • Drugs such as cocaine, antidepressants and some chemotherapy drugs
    In rare cases, dilated cardiomyopathy can be caused by pregnancy or rheumatoid arthritis.

    You are at a greater risk of developing dilated cardiomyopathy if you are:
    • An adult between the ages of 20 and 60 years old
    • A man. Three times as many men as women develop dilated cardiomyopathy
    • An African-American. Three times as many blacks as whites develop this condition.

    Symptoms

    The symptoms you experience if you have dilated cardiomyopathy depend on what has caused your condition.

    If an infection has caused cardiomyopathy, your first symptoms may be a sudden fever and feeling as if you have the flu.

    If the dilated cardiomyopathy occurs because of coronary artery disease, your first symptom may be shortness of breath when you are active and a tendency to get tired easily.

    In both cases, your heart rate eventually speeds up to try to get more blood pumped through the heart. Your blood pressure will be normal to low. You may experience swelling of the legs and abdomen as fluid collects. Eventually, your lungs will also fill with fluid.

    Dilated cardiomyopathy triggers a downward spiral of complications.

    Because the heart is enlarged, the valves between the upper chambers and the lower chambers - the mitral valve on the left side of the heart and the tricuspid on the right side - aren¿t able to close properly. This causes blood to leak through the valve, which in turns causes heart murmurs. Because the heart muscle has been damaged and stretched, irregular heart rhythms (arrhythmias) may develop. Both the leakage and the arrhythmia make it still harder for the heart to pump normally.

    Because the heart isn't pumping normally, blood pools in the chambers of the heart where it can clot on the walls of the heart's chambers. If these break off and travel through the blood vessels, they are called emboli. They can block blood vessels causing a variety of problems. It the blocked vessel is in the brain, a stroke can result. If it is in an artery of the heart, a heart attack can result.

    Diagnosis

    Your doctor will take your medical history, note your symptoms and do a physical examination. On the basis of that, he or she can make a diagnosis.
    Your doctor may also order tests such as:

    • An electrocardiogram. This may detect abnormal electrical activity in your heart. This alone, however, is not enough to make a diagnosis on.
    • Echocardiography. This is the most useful test because it can show the size and pumping action of the heart.
    • Magnetic resonance imaging (MRI). This produces very detailed images of the heart and can confirm a diagnosis of dilated cardiomyopathy.
    • Cardiac catheterization. This is an invasive procedure that is used only when the diagnosis remains in doubt after other tests. It provides information about the heart's ability to pump and also provides an opportunity to take a tissue sample for examination under a microscope. This, called a biopsy, can sometimes identify changes in tissue that are caused by infections, as in the case of viral cardiomyopathy.

    Treatment

    Dilated cardiomyopathy is a serious condition that gets worse over time. If abnormal heart rhythms start, the outlook becomes even more serious. There is no way to reverse the damage that is done to the muscles of the heart.

    Treatment usually consists of dealing with the underlying cause, such as not drinking alcohol if alcohol abuse was a factor or taking antibiotics if a bacterial infection was the cause. If the underlying cause was coronary artery disease that also should be treated, including taking a nitrate, a beta-blocker or a calcium channel blocker. However, calcium channel blockers may make the pumping action of the heart weaker. This may make heart failure that comes with dilated cardiomyopathy worse.

    Regardless of the cause of the condition, most people with dilated cardiomyopathy are given drugs that prevent blood clots, such as warfarin. It is important to get enough rest and to avoid stress or anything that strains the heart.

    Drugs to control abnormal heart rhythms may be given to some people. These types of drugs are usually started in small doses and built up slowly as too much can weaken the heart's pumping action.

    Because dilated cardiomyopathy is a disease that continues to get worse because of the all the interacting aspects of the condition, most patients eventually develop heart failure. In this case, your doctor may prescribe an angiotensin-converting enzyme (ACE) inhibitor, a beta blocker, digoxin and a diuretic to help eliminate the fluids that may collect in your body.

    Because of the life-threatening nature of dilated cardiomyopathy, it is the most common reason for heart transplantation.

    Hypertrophic cardiomyopathy

    Hypertrophic cardiomyopathy consists of several conditions in which the walls of the lower chambers of the heart (the ventricles) thicken (hypertrophy) and become stiff.

    Symptoms

    Symptoms of hypertrophic cardiomyopathy include:

    • Chest pain (angina). This usually occurs with activity.
    • Fainting (syncope). This occurs usually after activity because the heart can¿t pump enough blood to the brain after the heart rate has slowed down when the activity is over.
    • Irregular heartbeats (arrhythmia) or an awareness of heart palpitations. This happens because the stiff, thickened walls of the ventricles don¿t fill up with blood normally or completely empty blood from the ventricles.
    • Shortness of breath. This happens because the thickened, stiff muscle of the heart doesn't fill up with blood from the lungs. The blood pools in the veins of the lung and fluid collects in the lungs
    Persons with hypertrophic cardiomyopathy are at greater risk of developing infective endocarditis because the mitral valve which allows blood to flow from the left upper chamber (atrium) to the left lower chamber (ventricle) doesn't close normally. This allows blood to leak back into the atrium.

    Sometimes the thicken muscle blocks the flow of blood out of the heart below the aortic valve. This is called hypertrophic obstructive cardiomyopathy.

    Causes and Risk Factors

    Hypertrophic cardiomyopathy can be present at birth due to a defect in the heart. Other types develop later because of diseases such as acromegaly (an overproduction of growth hormone), neurofibromatosis or a tumor of the adrenal glands that causes too much of the hormone epinephrine to be produced.

    If affects men and women equally.

    Diagnosis

    Your doctor will take your medical history and do a physical examination. If you have hypertrophic cardiomyopathy, your heart will make typical sounds that your doctor can hear through a stethoscope.

    Your doctor will also try to rule out the possibility that your symptoms are due to     aortic stenosis or coronary artery disease.
    To confirm the diagnosis your doctor may order:

    • chest X-ray
    • Echocardiography
    • Electrocardiography
    Cardiac catheterization, which is an invasive procedure, allows your doctor to measure the pressure inside the chambers of the heart. This is done only if surgery is being considered.

    Treatment

    Treatment usally focuses on:

    • Eliminating the underlying cause, if possible. Examples include treating acromegaly with with a synthetic hormone to block the production of the growth hormone and removal of tumors or taking drugs to block the effects of epinephrine.
    • Increasing the heart's ability to fill with blood between heart beats. This can be done with beta-blockers and calcium-channel blockers, which tend to slow the heart rate and cause the heart muscle to contract less forcefully. This allows the blood to fill the heart more easily.
    If drug therapy is not effective and the symptoms are incapacitating, surgery can be done to remove some of the thickened heart muscle (myectomy). This helps relieve symptoms, but is not a cure for the condition.

    If the condition worsens to the point of heart failure, a
    heart transplant may be needed.

    Persons with hypertrophic cardiomyopathy should take antibiotics before any dental work or surgery to prevent the possibility of     infective endocarditis.

    Restrictive cardiomyopathy

    Restrictive cardiomyopathy (also sometimes called infiltrative cardiomyopathy) is a condition in which the walls of the lower chambers of the heart (the ventricles) become stiff but not necessarily thicker. The stiffness of the muscle walls prevents the heart's lower chambers from filling up normally with blood between heartbeats. It is one of several types of cardiomyopathy.

    The rarest form of cardiomyopathy, restrictive cardiomyopathy has much in common with hypertrophic cardiomyopathy.

    Symptoms

    Because restrictive cardiomyopathy prevents the heart from pumping blood in a normal way, many of its symptoms are those of heart failure including:

    • Abnormal heart rhythms (arrhythmias) and heart palpitations
    • Shortness of breath
    • Swelling as fluid collects in the tissue
    • Chest pain (angina) and fainting (syncope) may occur, but they are not as likely to as in hypertrophic cardiomyopathy.

    Causes and Risk Factors

    In most cases, it is not possible to identify what has made the walls of the ventricles becomes stiff. Restrictive cardiomyopathy can be caused by:

    • Abnormal deposits of protein, minerals or other substances in the heart muscle. For example, iron may collects in the heart muscle if a person has hemochromatosis. The protein amyloid may collect in the heart muscle of a person who has amyloidosis. Tumors or abnormal collections of certain white blood cells (granuloma tissue) may get into the heart if a person has sarcoidosis.
    • Scar tissue that has slowly replaced heart muscle as a result of injury such as that caused by radiation therapy for cancer

    Diagnosis

    If you have symptoms of heart failure, your doctor will check to see if restrictive cardiomyopathy is one the possible causes of your symmptoms.

    Your doctor will base his or her diagnosis on a:

    • Physical examination
    • Electrocardiogram (ECG), which may show abnormalities in the heart's electrical activity. This isn't usually specific enough to confirm a diagnosis of restrictive cardiomyopathy.
    • Echocardiography
    • Magnetic resonance imaging (MRI), which can detect abnormal textures in the tissues of the heart muscle, such as that caused by iron or amyloid.
    • Cardiac catheterization, which measures the pressures in the heart's chambers and allows a tissue sample to be taken for examination under a microscope is the most precise way to confirm the diagnosis.

    Treatment

    There is no cure for restrictive cardiomyopathy. Sometimes, treating an underlying condition (amyloidosis or hemochromatosis, for example) can help prevent the condition from getting worse.

    Treating the symptoms produced by the restrictive cardiomyopathy itself requires juggling steps to reduce the workload on the heart with making sure that the blood pressure isn't lowered so much that the symptoms become worse.

    Ironically, while many of the symptoms are the same as for heart failure, many treatments given to persons with heart failure aren't helpful to persons with restrictive cardiomyopathy. For example,     diuretics that are used to treat heart failure can reduce the amount of blood entering the heart and make restrictive cardiomyopathy. Drugs such as ACE inhibitors can also cause the blood pressure to go too low.

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