What is Myocarditis?: Causes, Risk Factors, Symptoms, and Treatments

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If you’ve never heard of myocarditis, you’re not alone. Read on for more information about the causes, risk factors, symptoms, treatments, and prevention of myocarditis.

What Is Myocarditis?

Myocarditis is a condition that causes your heart muscle to become inflamed or swollen and painful. The immune system protects your body by sending chemicals to defend against things that can hurt it. When these chemical levels are too high, your heart can’t do its job of pumping blood throughout the body. This can lead to serious heart problems.

Heart Inflammation

There are three main types of heart inflammation:

  • Myocarditis affects the heart muscle.
  • Pericarditis affects the area around the heart.
  • Endocarditis affects the inner lining of the heart.

Causes and Risk Factors

The cause of most myocarditis cases is not known. It can be caused by infections, health conditions, and certain drugs –including nonprescription substances.

Infections that can cause myocarditis include:

  • Bacterial infections (for example, staph or strep)
  • Viral infections (for example, Hepatitis C, COVID-19, HIV, influenza)

Health conditions that can increase the risk of myocarditis:

Autoimmune diseases like rheumatoid arthritis and lupus cause your immune system to target your own tissues instead of foreign organisms. This can lead to heart inflammation. 

There are also certain prescription medicines like some heart medications, diuretics (“water pills”), and cancer treatments that could cause myocarditis. Most people safely take these medications daily without developing myocarditis, which isn’t a common condition.

Some other risk factors for developing myocarditis:

  • Younger adults, between 20 and 40 years old, are diagnosed with myocarditis more frequently than older adults.
  • Heavy alcohol use can weaken your heart and increase the risk of myocarditis.

Using certain nonprescription drugs, such as cocaine, amphetamines, or injectable drugs, might damage the heart muscle.

Myocarditis Symptoms

Many people with myocarditis don’t have any symptoms. Some feel sudden chest pain that seems like a heart attack. 

The most common symptoms of myocarditis:

  • Chest pain (can feel severe and painful)
  • Shortness of breath (difficult or painful breathing)
  • Fatigue (feeling extremely tired, unable to exercise)
  • Irregular or fast heartbeat
  • Feeling faint or light-headed
  • Stomach pain
  • Swollen legs or feet
  • Flu-like symptoms, including fever, headache, and body aches


Myocarditis can be hard to diagnose because the symptoms might not be noticeable. There is no single way to diagnose myocarditis. However, doctors can look at symptoms and use a combination of tests and examinations to help identify them.

Some of these tests include:

  • Your doctor will perform a physical exam of your body and ask questions about your symptoms.
  • A chest x-ray can show your doctor the size and shape of your heart.
  • An electrocardiogram (ECG or EKG) can test the electrical activity of your heart to measure the rate and rhythm of heartbeats.
  • An echocardiogram (Echo, TTE) creates pictures of your heart to see if it is pumping blood correctly.
  • Cardiac MRI (magnetic resonance imaging) uses radio waves and magnets to look for signs of damage and incomplete blood flow.

Your doctor will also use blood tests to find out if there are unusual factors that could cause symptoms of myocarditis, including:

  • Blood cultures: Infectious disease tests look for bacteria or viruses that could cause myocarditis.
  • Complete blood count, or CMP: Increased numbers of white blood cells is often a sign of infection.
  • Erythrocyte sedimentation rate, or ESR: Measures how long it takes for red blood cells to settle in a test tube.
  • Troponin: Damaged heart muscles release this protein into the blood.
  • BNP, or brain natriuretic peptide: This result shows if your heart is pumping enough blood through your body.
  • Creatinine kinase-MB, or CKMB: Higher levels in the blood could mean that heart muscle is damaged.


Your treatment will focus on managing the cause of myocarditis and its symptoms. [Reader may wonder why antibiotics won’t cure cases caused by bacteria] There is no cure for myocarditis. The effects of myocarditis, such as chest pain, usually get better without treatment with medication or therapy.

Medicines to Treat Symptoms of Myocarditis

  • Aspirin or non-steroidal anti-inflammatory drugs (NSAIDs like ibuprofen) help with inflammation and pain.
  • Corticosteroids like prednisone or dexamethasone are also used to relieve pain and inflammation.
  • Diuretics can help get rid of extra fluid in the body to treat swelling and breathing problems.
  • Blood pressure and heart medications may be used to control high blood pressure and an irregular heartbeat.

If you have a severe case of myocarditis, you will need additional treatment and monitoring for abnormal heart rhythm or heart failure with devices like pacemakers. In the rare case of heart failure, you may need a heart transplant.

Recovery From Myocarditis

Many people developing myocarditis don’t have any symptoms, and many stop without medical treatment. Most patients with myocarditis recover in 3-6 months. Your doctor may advise you to rest and avoid activities that make your heart work harder until the symptoms are gone.


Myocarditis is not a common condition, and it is difficult to prevent, but healthy lifestyle choices can help. Here are some things that you can do to protect your heart and body:

  • Eat healthy, balanced meals and limit salt, sugar, and excess fat
  • Drink plenty of water daily
  • Limit alcohol to less than 1 drink per day
  • Don’t smoke cigarettes 
  • Engage in physical activity for 30 minutes a day, 5 days every week 
  • Follow directions for medicines that treat blood pressure, diabetes, and cholesterol
  • Keep all scheduled appointments at your doctor’s office

Next Steps

You should call your doctor if you have symptoms of myocarditis, such as sudden chest pain, shortness of breath, or if your heartbeats feel pounding or racing. Myocarditis symptoms make people feel like they are having a heart attack. 

If you have painful chest symptoms or difficulty breathing, call 911 or immediately go to your closest emergency room. If recognized quickly, many heart conditions can be treated to decrease heart damage.