Tests and diagnosis

By Mayo Clinic Staff

If you have symptoms associated with heart failure or arrhythmia — such as shortness of breath or fatigue — your doctor will order tests to check your heart's function, identify possible causes of your illness and decide on treatment. For some of the exams, your doctor may refer you to a heart specialist (cardiologist) or specialized technicians.

The results of some tests may help your doctor decide what additional tests to order.

  • Physical examination. Your doctor will review 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.

  • 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 tests may reveal if you have an infection, a metabolic disorder or toxins in your blood that can cause dilated cardiomyopathy.
  • 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.
  • 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. Your doctor may ask you to wear a portable ECG device known as a Holter monitor to record your heart rhythm for a day or two.
  • 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.

  • 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.
  • 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.
  • 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.
  • 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.

Sep. 16, 2011