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The patient may present variable degrees of cardiac enlargement, and findings of congestive heart failure. In advanced stages of the disease, the pulse pressure is narrowed and the jugular venous pressure is elevated. Third and fourth heart sounds are common. Mitral or tricuspid regurgitation may occur, presented by systolic murmurs upon auscultation (see mitral regurgitation and tricuspid insufficiency for more details about the findings).

Generalized enlargement of the heart is seen upon normal chest X-ray. Pleural effusion may also be noticed, which is due to pulmonary venous hypertension.The electrocardiogram often shows sinus tachycardia or atrial fibrillation, ventricular arrhythmias, left atrial abnormality, and sometimes intraventricular conduction defects and low voltage. Echocardiogram shows left ventricular dilatation with normal or thinned walls and reduced ejection fraction. Cardiac catheterization and coronary angiography are often performed to exclude ischemic heart disease.

Cardiomyopathy is usually discovered when the doctor is examining and testing you for the cause of heart failure. Tapping over the heart with the fingers and feeling the area may indicate that the heart is enlarged. Listening to the chest with a stethoscope reveals lung crackles, heart murmur, or other abnormal sounds. The liver may be enlarged. Neck veins may be bulging.

Children will have poor growth, pale skin, difficulty feeding, and weak pulses in the legs and arms.

Heart enlargement, congestion of the lungs, decreased movement/functioning of the heart, or heart failure may show on these tests:

1.Nuclear heart scan (MUGA, RNV)
2.Echocardiogram
3.Chest x-ray
4.Chest CT scan or MRI of the heart
5.Cardiac catheterization and coronary angiography

An ECG may show conduction disturbances or arrhythmias, including tachycardia, and may indicate enlargement of the ventricles. Heart biopsy may be helpful to distinguish dilated cardiomyopathy from other diseases. Lab tests vary depending on the suspected cause.

1.Cardiac catheterization:Your doctor may order a procedure called cardiac catheterization, which is used to check for factors that may cause dilated cardiomyopathy. A long, narrow tube is threaded through a blood vessel and into the heart with the use of X-ray technology to guide the cardiologist. The test can be used to see your coronary arteries on an X-ray, measure pressure in your heart, and collect a sample of muscle tissue to check for damage that shows you have dilated cardiomyopathy.

2.Computerized Tomography:Computerized tomography (CT) or magnetic resonance imaging (MRI) scan. In some situations your doctor may order a computerized tomography (CT) or a magnetic resonance imaging (MRI) scan of your heart. These tests can check the size and function of your heart’s pumping chambers and can sometimes provide clues to suggest unusual disorders that cause dilated cardiomyopathy.

3.Exercise stress test:Your doctor may have you perform an exercise test, either walking on a treadmill or riding a stationary bike. Electrodes attached to you during the test help your doctor measure your heart rate and oxygen use. This type of test can show the severity of problems caused by dilated cardiomyopathy.

4.Echocardiography:An echocardiogram uses sound waves to produce images of the heart. This common test lets your doctor see your ventricles squeezing and relaxing and valves opening and closing in rhythm with your heartbeat. The echocardiogram is the primary tool for diagnosing dilated cardiomyopathy. If you have dilated cardiomyopathy, your doctor will be able to observe enlargement of the left ventricle. An echocardiogram can also reveal how much blood is ejected from the heart with each beat and whether blood is flowing in the right direction.

5.Electrocardiogram (ECG):An electrocardiogram also called an ECG or EKG records electrical signals as they travel through your heart. Your doctor can look for patterns among these signals that show an abnormal heart rhythm or problems with the left ventricle.

6.Chest X-Ray:Your doctor may order a chest X-ray to check your heart and lungs. Although these images don’t provide enough information alone for making a diagnosis, they can reveal abnormalities in the heart’s structure and size and can detect fluid in or around your lungs. The chest X-ray can provide a baseline record of your heart from which to check for subsequent changes associated with your condition.

7.Blood Tests:Your doctor may order a series of blood tests that may show evidence of poor heart function or factors that can cause dilated cardiomyopathy. These may tests may reveal if you have an infection, a metabolic disorder or toxins in your blood that can cause dilated cardiomyopathy.

Physical Examination.Your doctor reviews your lifestyle habits (such as exercise, diet, smoking history and alcohol use), recent changes in weight, any signs and symptoms you’ve observed, and the history of heart disease and other medical conditions in your family.Your doctor will also check for signs such as irregular heartbeats, abnormal heart sounds (heart murmurs), the accumulation of fluids in the lungs, swelling in the legs or feet, or coolness in the limbs due to poor blood circulation.

Genetic Screening or Counseling.If your doctor can’t identify the cause of dilated cardiomyopathy, he or she may suggest screening of other family members to see if the disease is inherited in your family. No single test can determine if you carry a disease-related gene mutation. However, a thorough and detailed family history may reveal who’s most at risk of dilated cardiomyopathy or whether there’s evidence of other conditions that may contribute to the disease. Genetic testing is performed in some situations, usually as part of a research study.

The diagnosis and evaluation of dilated cardiomyopathy focuses upon determining if there are treatable or reversible causes. This process is described in detail in a separate topic review. (See “Patient information: Heart failure”, section on ‘Heart failure diagnosis’.)

Testing of family members — Between 30 and 50 percent of people with idiopathic dilated cardiomyopathy have inherited a genetic mutation for the disease. Some of these mutations can be identified with blood testing. People who have one or more family members who experienced sudden cardiac death or developed unexplained HF before age 60 should be evaluated by a genetics center that is experienced with cardiovascular diseases; a genetics counselor can help to determine if genetic testing would be helpful (see www.nsgc.org, click on “Find a counselor”).

If there is no family history of dilated cardiomyopathy, unexplained heart failure, or sudden cardiac death, first degree family members (eg, parents, siblings, children) of a person with DCM can consider screening tests, including an electrocardiogram and echocardiogram, to determine if there are early signs of DCM. However, there are a few caveats related to screening:

Having a single normal screening test does not mean that cardiomyopathy will not develop in the future. Screening tests are usually repeated every three to five years, unless symptoms develop sooner.

Screening tests cannot always predict which relatives will be affected by DCM or how severe the disease will be.

The initial symptoms of DCM are variable (shortness of breath, fainting, sudden death). In people with a family history of DCM, any new symptoms should be evaluated promptly.