Your doctor will take a personal and family medical history. Then, he or she will also do a physical exam using a stethoscope to listen to your heart and lungs, and order tests. Your doctor may refer you to a heart specialist (cardiologist) for testing.
Tests your doctor might order include:
- Blood tests. These tests give your doctor information about your heart. They also 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 for changes or abnormalities in the heart's structure and size, and for fluid in or around your lungs.
- 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 that may be a sign of an abnormal heart rhythm or problems with the left ventricle. Your doctor may ask you to wear a portable ECG device (Holter monitor) to record your heart rhythm for a day or two.
- Echocardiogram. This primary tool for diagnosing dilated cardiomyopathy uses sound waves to produce images of the heart, allowing your doctor to see whether your left ventricle is enlarged. This test 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. If you're unable to exercise, you may be given medication to create stress on your heart.
- CT or MRI scan. In some situations, your doctor might order one of these tests to check the size and function of your heart's pumping chambers.
Cardiac catheterization. For this invasive procedure, a long, narrow tube is threaded through a blood vessel in your arm, groin or neck into your heart. The test enables your doctor to see your coronary arteries on X-ray, measure pressure in your heart and collect a sample of muscle tissue to check for damage that indicates dilated cardiomyopathy.
This procedure may involve having a dye injected into your coronary arteries to help your doctor study your coronary arteries (coronary angiography).
- 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.