Myocarditis

Diagnosis

Mayo Clinic doctors with training in heart disease (cardiologists) work with specialists in many areas to diagnose myocarditis.

Myocarditis can be difficult to diagnose because it resembles many other diseases. Your doctor may suspect myocarditis if you have shortness of breath, the most common symptom, which typically develops seven to 14 days after a viral illness.

To diagnose myocarditis, your doctor discusses your medical history, conducts a comprehensive physical examination and orders laboratory tests to evaluate your heart's function.

Tests to diagnose myocarditis may include:

• Blood tests. Your doctor conducts blood tests to check for signs of infection or inflammation and measure enzyme levels that may signal damage to your heart. Blood tests may also reveal one of the viruses that has been linked to myocarditis.
• Chest X-ray. A chest X-ray shows the size and shape of your lungs and heart. A chest X-ray shows an enlarged heart and fluid buildup in your lungs, a sign of heart failure.
• Echocardiogram. An echocardiogram uses sound waves to produce a detailed video image of your heart's size, structure and function. The echocardiogram may show weak heart muscle, an enlarged heart or fluid surrounding the heart. Your doctor will usually conduct this test to diagnose myocarditis.
• Electrocardiogram. In this test, your doctor places sensor patches with wires attached (electrodes) on your skin to measure the electrical impulses given off by your heart. This test records the electrical activity of your heart, shows abnormal rhythms (arrhythmias or dysrhythmias) and detects heart muscle stress.
• Endomyocardial biopsy. In this test, your doctor inserts a thin, flexible tube (catheter) into a vein in your neck or groin. Your doctor uses a special tool to remove a small sample of your heart muscle to examine for signs of infection or inflammation.
• Holter monitor. A Holter monitor is a portable ECG device you wear for a day or more to record your heart's electrical activity during your daily routine.
• Magnetic resonance imaging (MRI). An MRI uses a magnetic field and radio waves to create detailed images of your body's organs and tissues. An MRI shows your heart function and inflammation of your heart muscle.

Read more about chest X-ray, echocardiogram, electrocardiogram, Holter monitor and MRI at MayoClinic.com.