Myocarditis is usually suspected based on an exam and blood tests. Imaging tests can help confirm myocarditis and the extent of the inflammation. These may include:
- Chest X-ray to show pictures of the heart, lungs, airways, and bones. It can show any areas of swelling in the heart.
- Heart MRI to look at the structure of the heart and see the heart working
- Echocardiogram to take a closer look at the structures of the heart and how it’s working
- Electrocardiogram (ECG) to measure the electrical activity of the heart and detect any abnormal heart rhythms
Blood tests can also help diagnose myocarditis. These may include tests to check for:
- Damage to the heart tissue (troponin)
- High levels of inflammation in the body (C-reactive protein, CRP or erythrocyte sedimentation rate, ESR or SED rate)
- Infection, which may include a complete blood count (CBC), blood cultures to see if the infection is in the bloodstream, or other tests
- Liver and kidney function
A biopsy to take a piece of tissue from the heart and examine it is the most accurate way to detect myocarditis. Because there are risks associated with this procedure, it is usually reserved for patients in whom a diagnosis using the heart tissue itself
would help to define the best treatment approach. The risks and benefits should be discussed as part of the decision-making process.
Sometimes, myocarditis is missed. That’s because the signs and symptoms are common to many other heart and lung conditions.