Dilated cardiomyopathy is the most common form of heart failure, and, in fact, most people - including many doctors - use the term "heart failure" as a synonym for dilated cardiomyopathy.
The term "cardiomyopathy" simply means heart muscle disease. In dilated cardiomyopathy (often referred to as congestive cardiomyopathy or congestive heart failure), the heart muscle, for one of many reasons, becomes damaged and weakened. In an attempt to compensate for this weakening, the heart muscle "stretches," causing the heart (especially the left ventricle) to dilate, or enlarge. So the hallmark of dilated cardiomyopathy is a weakened, enlarged heart.
What Causes Dilated Cardiomyopathy?Anything that can weaken the heart muscle can cause dilated cardiomyopathy - from coronary artery disease to viruses.
What Are the Symptoms of Dilated Cardiomyopathy?Dilated cardiomyopathy is the "classic" form of heart failure. Consequently it should not be a surprise that the symptoms of dilated cardiomyopathy are the classic symptoms of heart failure, namely, breathing difficulties, generalized weakness and cardiac arrhythmias.
If you have heart failure of any type, the carefully monitoring your own symptoms will be of immense help to your doctor in optimizing your treatment. So, it is important that you recognize the symptoms of heart failure and understand their significance.
How Is Dilated Cardiomyopathy Diagnosed?The diagnosis of dilated cardiomyopathy hinges on detecting the enlargement of the heart's chambers, especially the left ventricle. Detecting left ventricular dilation can most simply be accomplished using the echocardiogram, or a MUGA scan.
The 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. So, if the LVEF is 0.50 (which can also be expressed as a percentage, such as 50%), the left ventricle is ejecting half its blood volume with each heartbeat. A normal LVEF is 0.50 (50%) or greater. In dilated cardiomyopathy, the LVEF is invariably reduced below 0.5. The degree of reduction in LVEF is a good reflection of the amount of damage the left ventricle has sustained.
Once dilated cardiomyopathy is found, every effort should be made to identify a potentially reversible cause. In particular it is important to look for coronary artery disease and valvular heart disease. Anemia, abnormal tachycardias, nutritional deficiencies, alcoholism and thyroid disease also need to be ruled out. Rarely, a cardiac biopsy might need to be performed to help identify the underlying cause.
How Is Dilated Cardiomyopathy Treated?If you have dilated cardiomyopathy, it is critical that your doctor do a thorough investigation to try to find a reversible cause that can be treated and, in addition, to start each one of the therapies that have been shown to significantly improve the outcome of patients with this condition. Unfortunately, studies still show that a large proportion of patients with 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 doctor.
Hunt SA, Abraham WT, Chin MH, et al. 2009 focused update incorporated into the ACC/AHA 2005 Guidelines for the Diagnosis and Management of Heart Failure in Adults: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines: developed in collaboration with the International Society for Heart and Lung Transplantation. Circulation 2009; 119:e391.