An Overview of Dilated Cardiomyopathy Heart Failure

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Dilated cardiomyopathy is the most common of the three types of cardiomyopathy (heart muscle disease), the other two being hypertrophic cardiomyopathy and restrictive cardiomyopathy.

In dilated cardiomyopathy, the heart muscle becomes weakened and is unable to contract normally. To compensate for this weakening, the heart muscle "stretches," causing the heart (especially the left ventricle) to dilate. So the hallmark of dilated cardiomyopathy is a weakened, enlarged heart.

Potential Causes of Dilated Cardiomyopathy Heart Failure

Theresa Chiechi / Verywell


Dilated cardiomyopathy is the most common cause of heart failure. In fact, most people—including many healthcare providers—use the term "heart failure" as a virtual synonym for dilated cardiomyopathy. Consequently, it should not be a surprise that the symptoms of dilated cardiomyopathy are the classic symptoms of heart failure. These include dyspnea (shortness of breath), swelling in the feet and ankles, weakness, poor exercise tolerance, palpitations, and lightheadedness.


Anything that can weaken the heart muscle—which includes a surprising number of medical conditions—can lead to dilated cardiomyopathy. The more common conditions that can produce dilated cardiomyopathy include coronary artery disease (CAD), various infections, hypertension, and heart valve disease. Nutritional deficiencies, alcohol or cocaine abuse, pregnancy, cardiac arrhythmias, sudden emotional shock, genetic abnormalities, thyroid disease, and autoimmune disorders are among the other possible causes.


The diagnosis of dilated cardiomyopathy hinges on detecting the enlargement of the cardiac chambers, especially the left ventricle. Detecting left ventricular dilation can be accomplished most simply with an echocardiogram, or a MUGA scan.

A 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 which the left ventricle ejects with each heartbeat. A normal LVEF is 50 percent or higher (which means that normally the left ventricle ejects at least half its blood volume). In dilated cardiomyopathy, the LVEF is invariably reduced below 50 percent.

The degree of reduction in LVEF is generally an accurate reflection of the amount of damage the left ventricle has sustained. Repeating the LVEF measurement periodically can reveal whether a person’s cardiomyopathy is worsening or improving over time.


Once dilated cardiomyopathy is found, the first order of business should be to do a thorough evaluation to attempt to identify a potentially reversible cause. In this effort, no stone should be left unturned, because getting rid of the underlying cause is often the best way to halt cardiac deterioration, and in some cases to reverse it. In this regard, it is particularly important to look for CAD, heart valve disorders, nutritional deficiencies, hidden alcohol or cocaine usage, and thyroid disease. 

While looking for a potential underlying cause, aggressive treatment should be instituted to reduce symptoms, and also to stop cardiac deterioration. Several lines of therapy now have been shown to prolong survival and minimize symptoms in people who have dilated cardiomyopathy, and the therapy of this condition has been advancing rapidly.

Unfortunately, studies still show that a large proportion of people who have dilated cardiomyopathy are not receiving optimal care. If you or a loved one has dilated cardiomyopathy, you need to familiarize yourself with the therapy you ought to be receiving—and make sure you discuss it with your healthcare provider. It is generally a good idea to have a cardiologist oversee your care, both to be sure your treatment is up to standards, and to keep you informed of any potential breakthroughs in treating this very serious condition.

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