Symptoms
The symptoms of cardiomyopathy are similar to symptoms of heart failure. They include shortness of breath and/or fatigue with exertion or when lying down, waking up at night gasping for air, and swelling in the lower legs. As the disease progresses, so do the symptoms. Patients with dilated cardiomyopathy also have a greatly increased risk for life-threatening arrhythmias, such as ventricular tachycardia and ventricular fibrillation. Among these people, an episode of syncope (fainting) should be regarded as a harbinger of sudden death.
How Is Cardiomyopathy Diagnosed?
Diagnosis is made when a doctor can detect enlargement of the cardiac chambers, especially the ventricular chambers. Such enlargement can be seen on a chest x-ray, but can be more accurately assessed using an echocardiogram or a MUGA scan.One key piece of information obtained from either the echocardiogram or the MUGA scan is the left ventricular ejection fraction (LVEF), which is the proportion of its blood volume the left ventricle ejects with each heartbeat. So if the LVEF is 0.50 (which can also be expressed as a percentage, or 50%), the left ventricle is ejecting half its blood volume with each heartbeat. A normal LVEF is 0.50 (50%) or greater. The LVEF is a good reflection of the amount of damage the left ventricle has sustained due to a dilated cardiomyopathy.
Once dilated cardiomyopathy is found, every effort should be made to identify a potentially reversible cause. Coronary artery disease and valvular heart disease need to be ruled out. Anemia, abnormal tachycardias, nutritional deficiencies, alcoholism, and thyroid disease also need to be ruled out. Sometimes, a cardiac biopsy is performed to rule out active myocarditis.
What's the Long-Term Outlook of Dilated Cardiomyopathy?
Since it is generally causes no symptoms until actual heart failure sets in, by the time cardiomyopathy is diagnosed, heart disease is usually already fairly advanced. Usually, the pattern of a patient with dilated cardiomyopathy is characterized by episodes of severe heart failure that lead to hospitalization, followed by relatively long periods of "baseline" symptoms. During this baseline period, patients often have symptoms only with exertion. As time goes by, the episodes of severe heart failure become more frequent, and the "baseline" periods are characterized by a gradually worsening level of symptoms. In the year or so prior to death, frequent hospitalizations are common, and it is usually apparent to both patient and doctor that a steady, unrelenting deterioration is under way.To some degree, the LVEF can be a reflection of the prognosis in patients with dilated cardiomyopathy. Most people with dilated cardiomyopathy do not begin to experience significant symptoms until the LVEF is less than 40% (normal, again, being 50% or greater). When first diagnosed, most patients with dilated cardiomyopathy have LVEFs in a wide range, anywhere between 10% and 40%. In general, the lower the LVEF, the worse the prognosis.
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More on Dilated Cardiomyopathy
Causes of Dilated Cardiomyopathy
Treatment of Dilated Cardiomyopathy
Additional Links Related to Heart Failure
Sources:
Massie, BM "Heart Failure" in: Goldman L and Ausiello D (Eds). Cecil Textbook of Medicine, WB Saunders, 2003
