Patient education: Myocarditis (The Basics)

What is myocarditis? — Myocarditis is an inflammation of the heart (figure 1). It can affect the whole heart or just part of it. Myocarditis is often caused by a virus or autoimmune disease. In autoimmune diseases, the body's infection-fighting system attacks healthy tissue instead of infections. Autoimmune diseases can cause inflammation in the heart and other parts of the body. Other things, such as certain medicines, can also cause myocarditis.

Myocarditis can be mild or severe. There are different forms of myocarditis. Many forms get better on their own. Others can cause serious heart problems and even death.

What are the symptoms of myocarditis? — Myocarditis symptoms are different for each person. They depend on the type of myocarditis, the cause, and other factors. Symptoms can include:

●Heart failure – In this condition, the heart does not pump blood well. This can cause:

•Tiredness

•Less ability to exercise

•Swelling of the feet and legs

•Trouble breathing – This can be all of the time, just when active, or just when lying down.

●Chest pain

●Changes in heartbeat, such as beating fast or seeming to skip a beat

Should I see a doctor or nurse? — See your doctor or nurse if you have any of the symptoms listed above. Tell them if you recently had a cold or the flu, got a vaccine, or started taking a new medicine.

Will I need tests? — Yes. The doctor or nurse will ask about your symptoms and do an exam. You might have some or all of these tests:

●Blood tests – These measure the levels of enzymes that are normally in the heart. Myocarditis sometimes makes these enzymes leak out of the heart into the blood.

●Electrocardiogram ("ECG") – This test measures the electrical activity in the heart.

●Chest X-ray – An X-ray can show if there is fluid in the lungs and if the heart is larger than it should be.

●Echocardiogram (also called an "echo") – This test uses sound waves to create an image of the heart. It allows doctors to measure the walls and chambers of the heart, see how the heart is pumping, and check how the heart valves are working. Heart valves are flaps of tissue that open and close like swinging doors. They help keep blood flowing through the heart in 1 direction.

●MRI – This is an imaging test that uses a strong magnet to create pictures of the inside of the body. It can show the size of the heart and how well it is working. It can also show if there is damage to the heart.

●Cardiac catheterization (also called "cardiac cath") – During this test, the doctor puts a short tube called a "sheath" into a blood vessel in the leg or arm. The doctor can then pass a narrower tube or tools through the sheath to:

•Measure pressures inside the heart and blood vessels

•Do "coronary angiography" – In this test, the doctor puts a dye that shows up on X-rays into the tube. This test can show if any of the arteries in the heart are narrowed or blocked.

•Do a "biopsy" – In this test, the doctor puts a tiny tool through the tube. They use the tool to take a small piece of tissue from the heart. Another doctor looks at the tissue under a microscope to see if anything is wrong.

How is myocarditis treated? — Treatment for myocarditis depends on how severe it is and what caused it. Treatments can include:

●Medicines – Depending on the situation, doctors can give medicines to:

•Help you breathe better

•Keep fluid from building up

•Help keep your heart beating correctly

•Stop blood clots from forming

•Partly "turn off" your immune system

●Rest – Talk to your doctor about how much activity is right for you.

●Not drinking alcohol, or having no more than 1 drink a day

●If the myocarditis is severe, you might need other treatments. These include:

•Devices that a doctor puts in the body – Some devices help keep the heart beating correctly. Others help the heart pump blood.

•Heart transplant – In this surgery, a doctor replaces a diseased heart with a healthy heart.

People with myocarditis need to see a doctor or nurse regularly, even after they feel better. They also need tests to check how well the heart is working. This is because myocarditis can sometimes cause heart problems later.

More on this topic

Patient education: Chest pain (The Basics)
Patient education: Heart failure (The Basics)
Patient education: Heart transplant (The Basics)

Patient education: Chest pain (Beyond the Basics)
Patient education: Heart failure (Beyond the Basics)
Patient education: Heart transplantation (Beyond the Basics)