Diagnosis

Early diagnosis of myocarditis is important to preventing long-term heart damage. After a physical examination, your doctor might order one or more tests to confirm that you have myocarditis and determine its severity. Tests to diagnose myocarditis might include:

• Electrocardiogram (ECG or EKG). This quick and painless test shows your heart's electrical patterns and can detect abnormal heartbeats.
• Chest X-ray. An X-ray image shows the size and shape of your heart, as well as whether you have fluid in or around the heart that might be related to heart failure.
• Heart MRI (Cardiac MRI). A cardiac MRI shows your heart's size, shape and structure. This test can show signs of inflammation of the heart muscle.
• Echocardiogram. Sound waves create moving images of the beating heart. An echocardiogram can show your heart size and how well your heart is pumping. The test can also reveal valve problems, a clot within the heart or fluid around your heart.
• Blood tests. Blood tests used to diagnose or confirm myocarditis include a complete blood count and a test to check the levels of certain proteins (enzymes) that signal heart muscle damage. Other blood tests can be done to determine if you have antibodies against viruses and other organisms that might cause a myocarditis-related infection.
• Cardiac catheterization and heart muscle biopsy. A small tube (catheter) is inserted into a vein in your leg or neck and threaded into your heart. In some cases, doctors use a special instrument to remove a tiny sample of heart muscle tissue (biopsy) for analysis in the lab to check for inflammation or infection.