Dilated Cardiomyopathy

Exams and Tests

The first step in diagnosing dilated cardiomyopathy is a review of your medical history. Your health professional will ask about any recent illnesses, your alcohol and drug consumption, and your family history of heart disease.

Then he or she will do a thorough physical examination, including listening to your heart and lungs with a stethoscope. Since heart failure usually develops with dilated cardiomyopathy, your health professional will look for signs of heart failure, including:

• Unusual sounds, called heart murmurs, which may mean you have a problem with the heart's walls or valves. Pulmonary rales—crackles or bubbling sounds—heard in the chest may mean there is fluid buildup in the lungs.
• Fluid buildup may also be noted in the extremities, especially the legs and feet, and in bulging neck veins.

The following tests may also be done.

Echocardiogram: An echocardiogram is an ultrasound exam that uses high-pitched sound waves to create an image of the heart on a television screen. This painless and noninvasive test is the best and easiest way to diagnose dilated cardiomyopathy.

An echocardiogram, sometimes called an echo, estimates the heart's ejection fraction, a measurement of the heart's efficiency and the function of the left ventricle, the main pumping chamber. It also helps evaluate heart valve function and the shape and thickness of the heart chamber walls, which if stretched may indicate dilated cardiomyopathy.

Electrocardiogram: An electrocardiogram (ECG, EKG) is a record of the heart's electrical activity, including any abnormal heart rhythms (arrhythmias) resulting from dilated cardiomyopathy. It may also reveal areas that have been damaged by a heart attack.

Your doctor may also use a Holter monitor, a type of portable electrocardiogram that monitors your heart's electrical activity over a longer period of time (usually 24 hours). This may be done to check for any arrhythmias resulting from dilated cardiomyopathy.

Chest X-ray: A chest X-ray can show whether your heart is enlarged and whether there is fluid buildup in your lungs, a sign of heart failure.

Radionuclide ventriculogram:Radionuclide ventriculogram, also called nuclear scanning, measures ejection fraction. This is a useful diagnostic measurement because the ejection fraction is diminished in dilated cardiomyopathy.

During this test, a tiny dose of a radioactive substance (radioisotope) is injected into a vein. The movement of the gamma rays emitted by the radioisotope is followed through the heart chambers with a gamma camera, and the images are analyzed by a computer.

Coronary angiogram or coronary catheterization: In a coronary angiogram/catheterization, a thin, flexible tube is threaded through an artery or vein in the arm or groin and into the heart to measure pressure in the heart chambers and take samples of blood. Dye can also be injected through the catheter to see whether the arteries that supply the heart (coronary arteries) are blocked, how the heart chambers are pumping, and whether heart valves are leaking.

A myocardial biopsy, a sample of heart tissue, can be taken through the catheter and examined for signs of infection, metabolic disease, or a tumor. This procedure is usually reserved for people who have acute heart failure and who are not responding to treatment.

Electrophysiology study: An electrophysiology study (EP, EPS) is another way to study the heart's electrical activity. EP studies are used to evaluate arrhythmias or syncope and to assess the risk of sudden cardiac death.

For more information about exams and tests, see the topic Heart Failure.

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Author:	Robin Parks, MS	Last Updated: August 30, 2006
Medical Review:	Kathleen Romito, MD - Family Medicine E. Gregory Thompson, MD - Internal Medicine Stephen Fort, MD, MRCP, FRCPC - Interventional Cardiology
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