In medical terms, inflammation of the heart muscle is called myocarditis, derived from the word myocardium, which refers to the heart muscle itself. In severe cases, it can cause the heart to pump less effectively or beat irregularly, and it can have various causes. For example, it may result from a viral infection or an unexpected reaction to a medication. In some cases, inflammation in another part of the body can “spread” to the heart. People with myocarditis sometimes experience chest pain, fatigue, shortness of breath, or a rapid or irregular heartbeat. However, it can also occur without any symptoms. Severe myocarditis weakens the heart, preventing it from supplying enough blood to the rest of the body. Blood clots may form in the heart, which can lead to a stroke or heart attack. The risk of developing myocarditis is very low, and most people recover without complications. Inflammation can also affect the pericardium, the sac surrounding the heart. In this case, doctors refer to it as pericarditis, derived from pericardium. Myocarditis and pericarditis often occur together.

You should always see a doctor if you experience chest pain or shortness of breath. If you consider these symptoms to be severe, call emergency services or go to a hospital. In general, after an infection or a cold, it’s important to pay attention to your body and watch for the symptoms mentioned above.

Various diseases can be caused by viruses, bacteria, fungi, medications, or chemicals.^[1] In some cases, the body’s immune system reacts abnormally, leading to an autoimmune disease.^[2] However, the most common form is viral myocarditis.^[3] If left untreated, all of these conditions can sometimes damage the heart without noticeable symptoms. Below are some examples.^[1]

Viruses can cause the following illnesses:

• Common colds
• COVID-19
• Hepatitis B and C
• Gastrointestinal infections
• Herpes
• Epstein-Barr virus
• Rubella (German measles)
• HIV

These diseases are caused by the following bacteria:

• Staphylococci are responsible for many inflammations throughout the body
• Streptococci often lead to infections of the upper respiratory tract
• Corynebacterium diphtheriae causes diphtheria
• Borreliosis (Lyme disease) is caused by an infection with bacteria of the species Borrelia burgdorferi (Borrelia)

Parasites can also cause diseases, for example:

• Trypanosoma cruzi causes Chagas disease, which primarily affects people in Central and South America.
• Toxoplasma (T.) gondii causes toxoplasmosis, a common infectious disease. The parasite’s definitive host is the cat, where it reproduces in the intestines. However, birds, mammals, and humans can also become intermediate hosts.

Fungi can also be a cause of disease:

Infections can be caused by yeasts such as Candida, molds such as Aspergillus, and other fungi like Histoplasma, which is often found in bird droppings. For healthy individuals, these are usually harmless, but in patients with weakened immune systems, they can lead to myocarditis.

In general, any substances that trigger an allergic or toxic reaction in humans can also cause myocarditis. These include medications, illegal substances, as well as chemicals or harmful radiation.

In most cases, myocarditis heals on its own without lasting complications (in about 60–70% of cases [3]). However, severe inflammation of the heart muscle can cause permanent damage and lead to the following conditions:

• Heart failure: This occurs when the heart can no longer pump effectively. In severe cases, a heart transplant may even be necessary.
• Heart attack or stroke: These occur when blood clots form and block one or more arteries. If this happens in the heart, it leads to a heart attack; if it affects the brain, it results in a stroke.
• Rapid or irregular heart rhythms (arrhythmia)
• Sudden cardiac arrest: This is fatal if not treated immediately. In 5–20% of all sudden cardiac deaths, myocarditis is the underlying cause.^[3]

There is no specific way to prevent myocarditis, but you can take general measures to protect your health. Avoid contact with people who have viral or flu-like illnesses, and practice good hygiene to reduce your risk of infection. If you do get sick, give your body time to rest until you have fully recovered. Regular handwashing can also help prevent the spread of infections. Avoid risky behaviors: practice safe sex and do not use drugs. If you travel to areas where ticks transmit diseases, protect yourself by wearing long-sleeved shirts, long pants, and using insect repellent. Talk to your doctor about the benefits and risks of vaccinations and make sure you are up to date on recommended immunizations.

Early diagnosis of myocarditis is important to prevent serious heart damage whenever possible. In addition to an initial consultation and physical examination, your healthcare provider has several options to determine the severity of the condition.

List of possible diagnostic methods^[1,2]

• Electrocardiogram (ECG): This quick and painless test can detect and record irregular heartbeats, making arrhythmias visible.
• Cardisiography (CSG): Cardisiography provides a three-dimensional vector cardiogram of the heart’s electrophysiological properties. Using a patented algorithm and neural networks (AI), it detects pathological patterns of heart disease. It is used for the early detection of arterial, structural, and rhythm-related heart conditions. More information can be found here.
• X-ray: This shows the size and shape of the heart and can reveal whether fluid has built up in or around it.
• Cardiac MRI (magnetic resonance imaging): This imaging method creates detailed cross-sectional images of the size, shape, and structure of your heart, allowing signs of inflammation to be detected.
• Echocardiogram: Ultrasound waves create images of the beating heart. This test helps determine heart size and pumping function and can identify valve problems, deposits, or fluid accumulation.
• Blood tests: A complete blood count and specific protein tests can show if the heart muscle has been damaged. Blood tests can also detect antibodies against viruses and other pathogens.
• Cardiac catheterization and heart muscle biopsy: A thin tube (catheter) is inserted into a vein in your leg or neck and guided to your heart. With a special instrument, tiny samples of heart muscle tissue (biopsy) can be taken and examined in a laboratory for signs of inflammation or infection.

In many people, myocarditis heals on its own or requires only mild treatment. Depending on the severity, duration, and symptoms, there are also other therapeutic options.

• Medications: People with mild myocarditis may only need rest and medications, such as those that relieve pain and inflammation.
• Corticosteroids: These drugs suppress the immune system and can improve symptoms in certain rare forms of viral myocarditis, such as giant cell or eosinophilic myocarditis.
• Heart medications or therapies: If heart failure or arrhythmias occur due to inflammation of the heart, patients may need to stay in the hospital. Your doctor will treat you according to the findings, for example with medications that reduce the risk of blood clots forming in your heart. If heart failure is diagnosed, medications may also help reduce excess fluid or relieve strain on the heart. Common heart medications include diuretics, beta blockers, ACE inhibitors (angiotensin-converting enzyme inhibitors), or ARBs (angiotensin II receptor blockers).

If myocarditis is caused by another underlying disease, that condition must be treated first.

In severe cases, surgery or other interventions may be necessary, including medications administered intravenously or mechanical devices that support the heart (ventricular assist devices, or VADs). These can also include catheter-based procedures or extracorporeal membrane oxygenation (ECMO). In ECMO treatment, blood is pumped out of the body into the machine, oxygenated, and then returned to the body. This therapy is often used to support the heart during recovery from illness or as preparation for a heart transplant.

The course of myocarditis is difficult to predict. Some patients require medication for the rest of their lives, while many others recover completely. It is often recommended to avoid physical exertion until the condition has fully healed, which is usually after about six months.^[3]

Rest and recovery are important to allow your body to heal. You should coordinate any physical activity closely with your doctor. After a myocarditis diagnosis, patients should avoid intense or competitive sports for 3–6 months. If the heart has already sustained permanent damage, patients should avoid eating too much salt, drinking alcohol, or smoking. You can find tips for a heart-healthy diet on this page.

For mild symptoms, you should first see your general practitioner; for severe symptoms, go to the emergency room. Both will refer you to a cardiologist (heart specialist) if myocarditis is suspected. If you feel uncertain, you can bring a family member or friend with you for support.

Cases of myocarditis have been observed particularly in male adolescents and young adults within one week after the second dose of an mRNA COVID-19 vaccine. Most patients responded well to medication and rest and recovered quickly. After their symptoms subsided, many were able to return to their normal daily activities. According to the WHO, about 40.6 cases of myocarditis were reported per 1 million people who received two doses of the vaccine. The overall risk is considered to be very low. However, further studies are being conducted to collect more data. It has also been observed that myocarditis can occur following a COVID-19 infection itself. Anyone who experiences symptoms suggestive of myocarditis or pericarditis—such as chest pain, shortness of breath, or palpitations (see above)—should consult a doctor immediately.⁵

1. Mayoclinic.org: Myocarditis, Link https://www.mayoclinic.org/diseases-conditions/myocarditis/symptoms-causes/syc-20352539, abgerufen am 16.5.2022.
2. British Heart Foundation: Myocarditis, Link https://www.bhf.org.uk/informationsupport/conditions/myocarditis, abgerufen am 16.5.2022.
3. Austrian Journal of Cardiology: Die akute Myoperikarditis als Chamäleon – Fallpräsentation eines jungen Patienten, Link: https://www.kup.at/kup/pdf/12969.pdf, abgerufen am 16.5.2022.
4. Centers for Disease Control and Prevention: Myocarditis and Pericarditis After mRNA COVID-19 Vaccination, Link https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/myocarditis.html, abgerufen am 16.5.2022.
5. World Health Organization: COVID-19 subcommittee of the WHO Global Advisory Committee on Vaccine Safety (GACVS): updated statement regarding myocarditis and pericarditis reported with COVID-19 mRNA vaccines, Link: https://www.who.int/news/item/27-10-2021-gacvs-statement-myocarditis-pericarditis-covid-19-mrna-vaccines-updated, abgerufen am 16.5.2022.