DILATED CARDIOMYOPATHYDILATED CARDIOMYOPATHY
A. DEFINITION
C. SYMPTOMS
E. TREATMENTS
This type of cardiomyopathy is characterized by a dilatation and impaired contraction of the left or both ventricles. The heart pictured below is from a patient with dilated cardiomyopathy. Notice the dilated left ventricle.
This is a cardiac dysfunction that occurs when there is a dilation and impaired contraction of the left or both ventricles. This type of cardiomyopathy may be idiopathic, genetic, viral and/or immune, or associated with a cardiovascular disease. This is the most frequent form. The cavity of the heart is enlarged and stretched (cardiac dilation) in contrast to the thickening of the walls in the hypertrophic form. The heart is weak and does not pump blood efficiently. This causes decreased heart function that affects the lungs, liver, and other body systems.
Examples of specific dilated cardiomyopathies are an ischaemic cardiomyopathy which is present in the body when there is an imparied contractile performance that isn't explained by coronary artery disease or ischaemic damage. Hypertensive cardiomyopathy presents a left ventricular hypertrophy and occurs in association with dilated or restrictive cardiomyopathy and heart failure. Inflammatory myocardial disease is involved in pathogenesis of dilated cardiomyopathy and others and is defined by myocarditis in association with cardiac dysfunction.
Cardiomyopathies have many causes, including nutritional deficiencies, deposits in the heart muscle associated with medical conditions, anemia, stress, viral infections (rare), alcoholism, coronary artery disease, and others. However, in dilated cardiomyopathy, there is no identifiable cause, although it is suspected to be an end stage of myocarditis. It can affect all ages and both sexes, but is most common in adult men. Risk factors for dilated cardiomyopathy include obesity, personal or family history of cardiac disorders such as myocarditis, use of certain medications, smoking, and alcoholism. Cardiomyopathy also occurs when there is damage to the heart, resulting in scarring (fibrosis) or deposits in the tissues of the heart muscle.
Symptoms often develop gradually and usually include symptoms of right heart failure and/or left heart failure. In order to prevent symptoms for dilated cardiomyopathy from occuring, patients must modify controllable risk factors. Patients should eat a generally well-balanced, nutritious diet, exercise to improve cardiovascular fitness, and avoid or minimize smoking and consumption of alcohol.
Signs indicating dilated cardiomyopathy include symptoms such as, shortness of breath on exertion, fatigue, orthopnea (breathing difficulty when lying down), waking up at night short of breath, swelling of the ankles, excessive urination at night, irregular heartbeat (palpitations--a feeling of racing or skipping of the heart), decreased urine output (may not include at night).
Dilated cardiomyopathy is unfortunately diagnosed when it is discovered as the cause of heart failure. Upon physical examination, an irregular or a rapid heartbeat may be revealed. There may be distended neck veins, enlarged liver, dependent edema, and signs of pleural effusion (fluid around the lungs). Listening to the chest with a stethoscope may reveal lung crackles or abnormal heart sounds. Blood pressure may be low or may drop upon rising (orthostatic hypotension).
Heart enlargement, congestion of the lungs, decreased movement/functioning of the heart, decreased cardiac output, or heart failure may show up on an echocardiogram (an ECG may also show arrhythmias or other abnormalities), chest X-ray, chest CT scan, coronary angiography, and nuclear heart scans (MUGA, RNV)
A heart biopsy may be helpful to rule out other causes of cardiomyopathy. However, surgery is always the last resort to finding a dilated cardiomyopathy.
Hospitalization may be required of patients when symptoms of dilated cardiomyopathy are severe. Treatment for dilated cardiomyopathy is focused on relief of symptoms, just as is for other types of cardiomyopathy, and is essentially the same as the treatment of heart failure. Medications may include digitalis or other cardiac medications, diuretics, nutritional supplements, and other medications. A low-salt diet may be recommended to patients and fluid intake may be restricted in some cases. Daily weight records should be kept because a weight gain of 3 or 4 pounds or more over 1 or 2 days may indicate fluid accumulation. Physical activity may be restricted as symptoms progress. Smoking and alcohol cessation recommendations may be given, because these habits make symptom of dilated cardiomyopathy worse. A heart transplant may be considered if heart function is very poor.
Complications of dilated cardiomyopathy include congestive heart failure, cardiac arrhythmias, including lethal arrhythmias, pulmonary (lung) edema, total failure of the heart to function (circulatory collapse), and side effects of medications, including low blood pressure (hypotension), light headedness, fainting, lupus reaction, headache, GI upset, and digitalis toxicity. The expectations of dilated cardiomyopathy patients varies. There is no known cure for dilated cardiomyopathy. Some affected individuals remain stable for long periods, some deteriorate gradually, and some deteriorate rapidly.
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