congestive cardiomyopathy


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Related to congestive cardiomyopathy: Dilated cardiomyopathy

Congestive Cardiomyopathy

 

Definition

Cardiomyopathy is an ongoing disease process that damages the muscle wall of the lower chambers of the heart. Congestive cardiomyopathy is the most common form of cardiomyopathy. In congestive cardiomyopathy, also called dilated cardiomyopathy, the walls of the heart chambers stretch (dilate) to hold a greater volume of blood than normal. Congestive cardiomyopathy is the final stage of many heart diseases and the most common condition resulting in congestive heart failure.

Description

About 50,000 Americans develop cardiomyopathy each year. Of those, 87% have congestive cardiomyopathy. Primary cardiomyopathy accounts for only 1% of all deaths from heart disease.
When the heart muscle is damaged by a disease process, it cannot pump enough blood to meet the body's needs. Uninjured areas of the walls of the two lower heart chambers (called ventricles) stretch to make up for the lost pumping action. At first, the enlarged chambers allow more blood to be pumped with less force. The stretched muscle can also contract more forcefully. Over time, the heart muscle continues to stretch, ultimately becoming weaker. The heart is forced to work harder to pump blood by beating faster. Eventually it cannot keep up, and blood backs up into the veins, legs, and lungs. When this happens, the condition is called congestive heart failure.
Congestive cardiomyopathy usually affects both ventricles. Blood backed up into the lungs from the left ventricle causes fluid to congest the lung tissue. This is called pulmonary edema. When the right ventricle fails to pump enough blood, blood backs up into the veins causing edema in the legs, feet, ankles, and abdomen.

Causes and symptoms

Congestive cardiomyopathy may be caused by a number of conditions. Cardiomyopathy with a known cause is called secondary cardiomyopathy. When no cause can be identified, it is called primary cardiomyopathy or idiopathic cardiomyopathy. About 80% of all cases of cardiomyopathy do not have a known cause. Many heart specialists think that many cases of idiopathic congestive cardiomyopathy may be caused by a viral infection. Because cardiomyopathy may occur many years after a viral infection and viruses sometimes go undetected in laboratory tests, it is difficult to know if a virus is the cause. Some people have a weak heart from advanced coronary artery disease that causes heart muscle damage. This is sometimes called ischemic cardiomyopathy.
Conditions that can cause congestive cardiomyopathy are:
  • coronary artery disease
  • infections
  • noninfectious inflammatory conditions
  • alcohol and other drugs or toxins
  • hypertension
  • nutritional and metabolic disorders
  • pregnancy
Coronary artery disease is one of the most common causes of congestive cardiomyopathy. In coronary artery disease, the arteries supplying blood to the heart become narrowed or blocked. When blood flow to an area of the heart is completely blocked, the person has a heart attack. The heart muscle suffers damage when its blood supply is reduced or blocked. Significant recurrent muscle damage can occur silently. This damage can lead to congestive cardiomyopathy.
Infections caused by bacteria, viruses, and other microorganisms can involve the heart, causing inflammation of the heart muscle (myocarditis). The inflammation may damage the heart muscle and cause congestive cardiomyopathy. In the United States, the coxsackievirus B is the most common cause of viral congestive cardiomyopathy.
Myocarditis can also be caused by noninfectious disorders. For example, the conditions sarcoidosis, granulomatous myocarditis, and Wegener's granulomatosis cause inflammation and tissue death in the heart muscle.
Years of drinking excessive amounts of alcohol can weaken the heart muscle, leading to congestive cardiomyopathy. Other drugs and toxins, such as cocaine, pesticides, and other chemicals, may have the same effect.
High blood pressure (hypertension) puts extra pressure on blood vessels and the heart. This increased pressure makes the heart work harder to pump blood, which may thicken and damage the chamber walls.
Severe nutritional deficiencies can weaken the heart muscle and affect its pumping ability. Certain disorders of metabolism, including diabetes mellitus and thyroid disorders, can also lead to congestive cardiomyopathy.
Occasionally, inflammation of the heart muscle and congestive cardiomyopathy may develop late in pregnancy or shortly after a woman gives birth. This type of congestive cardiomyopathy is called peripartum cardiomyopathy. The cause of congestive cardiomyopathy in pregnancy is not known.
Congestive cardiomyopathy usually is a chronic condition, developing gradually over time. Patients with early congestive cardiomyopathy may not have symptoms. The most common symptoms are fatigue and shortness of breath on exertion. Unfortunately, sudden cardiac death is not uncommon with this condition. It stems from irregular heart rhythms in the ventricles (ventricular arrhythmias).
Patients with more advanced congestive cardiomyopathy may also have chest or abdominal pains, extreme tiredness, dizziness, and swelling of the legs and ankles.

Diagnosis

Diagnosis of congestive cardiomyopathy is based on:
The diagnosis is based on the patient's symptoms, a complete physical examination, and tests that detect abnormalities of the heart chambers. The physician listens to the heart with a stethoscope to detect abnormal heart rhythms and heart sounds. A heart murmur might mean that the heart valves are not closing properly due to the ventricles being enlarged.
A chest x ray can show if the heart is enlarged and if there is fluid in the lungs. Abnormalities of heart valves and other structures may also be seen on a chest x ray.
An electrocardiogram provides a record of electrical changes in the heart muscle during the heartbeat. It gives information on the heart rhythm and can show if the heart chamber is enlarged. An ECG can detect damage to the heart muscle and the amount of damage.
Echocardiography uses sound waves to make images of the heart. These images can show if the heart wall or chambers are enlarged and if there are any abnormalities of the heart valves. Echocardiography can also evaluate the pumping efficiency of the ventricles.
Cardiac catheterization usually is only used if a diagnosis cannot be made with other methods. In cardiac catheterization, a small tube (called a catheter) is inserted into an artery and passed into the heart. It is used to measure pressure in the heart and the amount of blood pumped by the heart. A small tissue sample of the heart muscle can be removed through the catheter for examination under a microscope (biopsy). This biopsy can show the type and amount of damage to the heart muscle.

Treatment

When a patient is diagnosed with congestive cardiomyopathy, physicians try to find out the cause. If coronary artery disease is not the culprit, in most other cases a cause is not identified. When a condition responsible for the congestive cardiomyopathy is diagnosed, treatment is aimed at correcting the underlying condition. Congestive cardiomyopathy caused by drinking excess alcohol or by drugs or toxins can be treated by eliminating the alcohol or toxin completely. In some cases, the heart may recover after the toxic substance is removed from the body. Bacterial myocarditis is treated with an antibiotic to eliminate the bacteria.
There is no cure for idiopathic congestive cardiomyopathy. Medicines are given to reduce the workload of the heart and to relieve the symptoms.
One or more of the following types of medicines may be prescribed for congestive cardiomyopathy:
Digitalis helps the heart muscle to have stronger pumping action. Diuretics help eliminate excess salt and water from the kidneys by making patients urinate more often. This helps reduce the swelling caused by fluid buildup in the tissues. Vasodilators, beta blockers, and ACE inhibitors lower blood pressure and expand the blood vessels so blood can move more easily through them. This action makes it easier for the heart to pump blood through the vessels.
Patients may also be given anticoagulant medications to prevent clots from forming due to pooling of blood in the heart chambers. Medicines to prevent abnormal heart rhythms (arrhythmias) may be given, but some of these drugs can also reduce the force of heart contractions. Automatic implantable cardioverter defibrillators (AICDs) can treat life-threatening arrhythmias, which are relatively common in severe cardiomyopathy.
Certain lifestyle changes may help reduce the workload on the heart and relieve symptoms. Some patients may need to change their diet, stop drinking alcohol, begin a physician-supervised exercise program, and/or stop smoking.
Severe congestive cardiomyopathy usually causes heart failure. When the heart muscle is damaged so severely that medicines cannot help, a heart transplant may be the only remaining treatment to be considered.

Prognosis

The outlook for a patient with congestive cardiomyopathy depends on the severity of the disease and the person's health. Generally, congestive cardiomyopathy worsens over time and the prognosis is not good. About 50% of patients with congestive cardiomyopathy live for five years after the diagnosis. Twenty five percent of patients are alive 10 years after diagnosis. Women with congestive cardiomyopathy live twice as long as men with the disease. Many of the deaths are caused by sudden abnormal heart rhythms.

Prevention

Because idiopathic congestive cardiomyopathy does not have a known cause, there is no sure way to prevent it. The best way to prevent congestive cardiomyopathy is to avoid known causes such as drinking excess alcohol or taking toxic drugs. Eating a nutritious diet and getting regular exercise to improve overall fitness also can help the heart to stay healthy.
Congestive cardiomyopathy may also be prevented by identifying and treating any conditions that might damage the heart muscle. These include high blood pressure and coronary artery disease. Regular blood pressure checks and obtaining immediate medical care for hypertension and symptoms of coronary artery disease, such as chest pain, are important to keep the heart functioning properly.
Finally, diagnosing and treating congestive cardiomyopathy before the heart becomes severely damaged may improve the outlook.

Resources

Organizations

American Heart Association. 7320 Greenville Ave. Dallas, TX 75231. (214) 373-6300. http://www.americanheart.org.
National Heart, Lung and Blood Institute. P.O. Box 30105, Bethesda, MD 20824-0105. (301) 251-1222. http://www.nhlbi.nih.gov.
Texas Heart Institute. Heart Information Service. P.O. Box 20345, Houston, TX 77225-0345. http://www.tmc.edu/thi.

Key terms

Angiotensin-converting enzyme (ACE) inhibitor — A drug that relaxes blood vessel walls and lowers blood pressure.
Atherosclerosis — Buildup of a fatty substance called a plaque inside blood vessels.
Cardiac catheterization — A diagnostic test for evaluating heart disease; a catheter is inserted into an artery and passed into the heart.
Cardiomyopathy — Disease of the heart muscle.
Congestive cardiomyopathy — Also called dilated cardiomyopathy; cardiomyopathy in which the walls of the heart chambers stretch, enlarging the heart ventricles so they can hold a greater volume of blood than normal.
Coxsackievirus B — A type of virus in the group Enterovirus that causes an infection similar to polio, but without paralysis.
Digitalis — A drug that helps the heart muscle to have stronger pumping action.
Dilated cardiomyopathy — Also called congestive cardiomyopathy; cardiomyopathy in which the walls of the heart chambers stretch, enlarging the heart ventricles so they can hold a greater volume of blood than normal.
Diuretic — A type of drug that helps the kidneys eliminate excess salt and water.
Edema — Swelling caused by fluid buildup in tissues.
Granulomatous myocarditis — Also called giant cell myocarditis, this noninfectious inflammation of the heart causes large areas of tissue death in the heart muscle, ventricular enlargement, and clots inside the heart chambers.
Idiopathic cardiomyopathy — Cardiomyopathy without a known cause.
Sarcoidosis — A chronic disease that causes formation of abnormal areas containing inflammatory cells, called granulomas, in any organ or tissue; in the heart, large areas of the heart muscle can be involved, causing cardiomyopathy.
Vasodilator — Any drug that relaxes blood vessel walls.
Ventricle — One of the two lower chambers of the heart.
Wegener's granulomatosis — A disease usually affecting males that causes the infiltration of inflammatory cells and tissue death in the lungs, kidneys, blood vessels, heart, and other tissues.

cardiomyopathy

 [kahr″de-o-mi-op´ah-the]
a general diagnostic term designating primary myocardial disease.
alcoholic cardiomyopathy a congestive cardiomyopathy resulting in cardiac enlargement and low cardiac output occurring in chronic alcoholics; the heart disease in beriberi (thiamine deficiency) is also associated with alcoholism.
congestive cardiomyopathy a syndrome characterized by cardiac enlargement, especially of the left ventricle, myocardial dysfunction, and congestive heart failure.
hypertrophic cardiomyopathy an increase in heart muscle weight, particularly of the left ventricle and often involving the interventricular septum; it may affect the flow of blood from an atrium into the ventricle or out from the ventricle. This type of cardiomyopathy is frequently associated with idiopathic hypertrophic subaortic stenosis. Called also asymmetrical septal hypertrophy.
hypertrophic obstructive cardiomyopathy a form of hypertrophic cardiomyopathy in which the location of the septal hypertrophy causes obstructive interference to left ventricular outflow. See also asymmetrical septal hypertrophy.
infiltrative cardiomyopathy myocardial disease resulting from deposition in the heart tissue of abnormal substances, as may occur in amyloidosis, hemochromatosis, and other disorders.
primary cardiomyopathy that in which the basic pathologic process involves the myocardium itself and not other cardiac structures; the condition is of unknown etiology and not part of a disease affecting other organs.
restrictive cardiomyopathy a form in which the ventricular walls are excessively rigid, impeding ventricular filling; it is marked by abnormal diastolic function but normal or nearly normal systolic function.
secondary cardiomyopathy any form that is due to another cardiovascular disorder or is a manifestation of a systemic disease such as sarcoidosis.

di·lat·ed car·di·o·my·op·a·thy

decreased function of the left ventricle associated with its dilation; most patients have global hypokinesia, although discrete regional wall movement abnormalities may occur; usually manifested by signs of overall cardiac failure, with congestive findings, as well as by fatigue indicative of a low output state.

congestive cardiomyopathy

Etymology: L, congerere, to accumulate; Gk, kardia, heart, mys, muscle, pathos, disease
a heart muscle disease characterized by heart failure and enlargement.

congestive cardiomyopathy

Dilated cardiomyopathy, see there.

cardiomyopathy

a general diagnostic term designating primary myocardial disease of unknown cause.

Boxer cardiomyopathy
a dilated cardiomyopathy, believed to be inherited, is seen in adult Boxers that show syncope, episodic weakness, arrhythmias, and left or biventricular heart failure.
congestive cardiomyopathy
a syndrome characterized by cardiac enlargement, especially of the left ventricle, poor myocardial contractility, and congestive heart failure. Occurs most commonly in young to middle-aged dogs of the large and giant breeds with rapidly developing signs of biventricular failure, atrial fibrillation and occasionally systolic murmurs. Cats usually show acute signs of cardiac failure with pleural effusion but not ascites, and sometimes thromboembolism. Called also dilated cardiomyopathy.
Doberman cardiomyopathy
a distinctive cardiomyopathy is seen in Doberman pinscher dogs, often presenting as an acute pulmonary edema, cardiogenic shock and sometimes sudden death.
hypertrophic cardiomyopathy
occurs most commonly in cats, sometimes secondary to hyperthyroidism, occasionally in dogs and rarely in cattle in association with generalized glycogenosis. There is myocardial hypertrophy, primarily in the left ventricle and ventricular septum, resulting in increased resistance to filling and sometimes an outflow obstruction. In cats there is often an associated aortic thromboembolism.
infiltrative cardiomyopathy
myocardial disease secondary to deposition in the heart tissue of abnormal substances such as amyloid or neoplastic infiltration.
inherited cardiomyopathy
occurs in calves and probably in the other species. In calves it causes death due to acute heart failure up to the age of 3 months. Recorded in polled Hereford and Japanese black cattle. There may be a brief period of dyspnea and blood-stained frothy nasal discharge before death. Myocardial degeneration is obvious at necropsy.
occult cardiomyopathy
in the subclinical stage, but detectable with echocardiography and ambulatory electrocardiographic recording methods.
restrictive cardiomyopathy
impaired left ventricular compliance reduces ventricular filling. Uncommon in animals but seen most often in cats, caused by endomyocardial fibrosis or abnormal left ventricular moderator bands. Called also obliterative cardiomyopathy.