Myocarditis

If you’ve been diagnosed with myocarditis or you think you have symptoms of myocarditis, it can be worrying. But with treatment most people will make a very good recovery. Some people will have more serious complications and will need specialist treatment.

On this page 

• Myocarditis explained 
• Link between myocarditis and pericarditis 
• Symptoms of myocarditis
• Myocarditis chest pain
• Causes of myocarditis
• Diagnosing myocarditis 
• Treating myocarditis
• Curing myocarditis 
• Work and myocarditis
• Exercise and myocarditis
• How to get support

Myocarditis explained

Myocarditis is a disease that causes inflammation of the heart muscle (the myocardium). Inflammation is your body’s natural way of fighting things that can harm it, such as infections or injuries. It can cause symptoms that affect your daily life.

Myocarditis can develop suddenly (acutely), can be recurring or it can be long-lasting (chronic). Most people will recover without any lasting effects. But in rare cases, if the inflammation is severe, myocarditis can scar the heart muscle. This damage means the heart has to work harder to pump blood and oxygen around the body. In some cases, this can result in the heart muscle becoming bigger, and over time, weaker.

Sometimes, myocarditis can affect the heart’s electrical system, leading to an irregular heart beat (arrythmia).

Link between myocarditis and pericarditis

Myocarditis can sometimes happen together with pericarditis (inflammation of the lining around the heart) and they have similar symptoms. If you have both myocarditis and pericarditis, this is sometimes known as myopericarditis.

• We can help you to live with myocarditis – find the right support for you. 

Symptoms of myocarditis

People with myocarditis can get chest pain and feel breathless. It’s not unusual for these symptoms to start up to two weeks after being unwell with an infection. Common symptoms of myocarditis include: 

• chest pain or discomfort, or a feeling of tightness in the chest
• shortness of breath, either at rest or when active, or in certain positions, such as lying down
• unusual tiredness
• palpitations (like your heart is fluttering, racing, or pounding) 
• an irregular heartbeat
• feeling light-headed or fainting
• Recent flu-like symptoms such as high temperature, headaches, body aches, joint pain, or sore throat 
• Rarely, swelling in hands, legs, ankles or feet. 

Some people have no symptoms, and their myocarditis may be picked up as part of a routine health appointment.

If you think you have symptoms of myocarditis, contact your doctor straightaway, or call NHS 111. Getting diagnosed and treated early can help you feel better and lower your risk of long-term complications from myocarditis.

Myocarditis chest pain

It’s common to feel a sensation of tightness or squeezing in the chest, either when at rest or when active. It could also happen if you’re lying down. You may have chest pain that feels sharp or stabbing, and chest pain/discomfort may spread to other parts of your body.

If the inflammation in your heart muscle also affects the lining of the heart (pericardium), your chest pain may feel better when you lean forward, and worse when you lie back.  

Inflammation can also cause extra heart beats that feel like a flutter in your chest. And if you have a run of a lot of extra beats together you may also feel light-headed.

Causes of myocarditis

Myocarditis is most commonly caused by: 

• a virus, such as the flu or Covid-19, or another viral infection.

If you’re worried, you can read more about the effect of Covid-19 on the heart, including how it can cause myocarditis.

When myocarditis is caused by a virus, symptoms can start to show one or two weeks later. This is because the immune system, the body’s own natural defence system, overreacts to being infected with a virus, and causes inflammation. This inflammation can stay in the heart even after the virus has gone.

Other causes include:

• bacterial infections, such as sore throat, or chest infection, or fungal infections, such as athlete’s foot
• auto immune diseases (when your own immune system attacks your body), for example lupus
• a reaction to harmful substances (toxins), such as carbon monoxide, or drugs such as cocaine
• a reaction to certain medicines or vaccines
• There have been rare cases of myocarditis following the Moderna covid vaccine (or even more rarely, the Pfizer vaccine). If you are worried, you can find out more about what covid vaccines mean for your heart.

Sometimes it isn’t possible to find the cause of myocarditis. This can be frustrating and difficult for you. There is support available to help you manage your condition and your wellbeing – find out how we can help.

Myocarditis can affect anyone, of any age, but it tends to affect more males than females, and people under 50.

Diagnosing myocarditis

Your doctor will examine you physically and ask you questions, including important information such as: 

• recent illnesses,  
• any history of auto-immune problems,   
• exposure to toxins/drugs
• other risk factors, for example if you’ve recently had a baby.

You may have tests, including: 

• an ECG (electrocardiogram) 
• an echo (echocardiogram) 
• a chest X-ray 
• blood tests.

These tests will help your doctor with your diagnosis.  These tests are very common, don’t take long (sometimes just a few minutes), and most people don’t feel any pain or discomfort when having them.  Other tests such as cardiac MRI and coronary angiogram may be done to help rule out other common cardiac causes.

In very rare cases a heart biopsy may be considered. This is where the doctor takes a tissue sample from your heart muscle (myocardium) for analysis.

BHF-funded researchers are developing the first-ever blood test for myocarditis, which they hope will lead to speedy diagnosis.

Treating myocarditis

Your treatment will depend on your symptoms and the cause of them.  Your doctor will discuss the best treatment options with you.

Treatment can include:

• painkillers/analgesia for the chest pain 
• medication to calm the inflammation, (your doctor will discuss suitable anti-inflammatory medicines with you)
• antibiotics, if a bacterial infection is the cause
• rest 
• general remedies if you feel unwell, such as plenty of fluids, rest and painkillers.

Your doctor will want to watch your progress and may ask you to come back for check-ups occasionally, although these may only be once a year.  It’s important to go to your appointments even if you feel well.  Going to these appointments will help give you the support you need.

For some people, myocarditis can scar the heart muscle, so it can’t pump blood around the body as well as it should. The heart becomes enlarged, and weaker. This is sometimes called dilated cardiomyopathy (DCM) or heart failure.

• Read more about dilated cardiomyopathy. 
• Read more about heart failure.

Questions to ask your doctor

Your doctor will discuss treatments and explain which one is right for you. Some people find it useful to think about questions to ask before an appointment and write these down on paper, or on their phone, so they don’t forget to discuss them with their doctor. Questions you might find helpful to ask your doctor include: 

• What is my follow-up plan?
• Any tips for managing symptoms?  
• How and when can I exercise again?
• How and when can I return to work?

You may have questions that feel embarrassing or uncomfortable to talk about.  Whatever question you have, your doctor has talked to lots of other people about them too. You won’t be the first or the last person to ask. It may not be easy to open up at first, but most people say they feel a lot better afterwards and are glad they did.

Other things that might help

• Use pillows to get into a comfortable position – some people find sitting forward with arms resting on a table helps, others might find using more pillows when sleeping helps
• Wear light, loose fitting clothes
• Stay hydrated
• Follow a healthy diet with plenty of fruit and veg

Curing myocarditis

Yes – most people will have one episode of myocarditis and will get better with rest, medication and avoiding high intensity exercise while their heart recovers. Doctors will follow your progress closely at first, and then you may be offered a yearly follow up appointment depending on your circumstances.

For some people myocarditis will last longer, or return. If your heart is damaged (scarred) by the inflammation, doctors will check your progress closely, with follow-up appointments at least every few months.

If your symptoms return, you should see a doctor straightaway or phone 111.

Work and myocarditis? 

You may need a time to rest, so depending on how serious your symptoms are and what work you do, you may need to take time off work.

If you’re not well enough to go to work, or if work is holding up your recovery, you can get a “fit note” (Statement of Fitness to Work) from your GP, or in England and Wales, nurses, pharmacists, occupational therapists and physiotherapists will also be able to write fit notes.

It can feel difficult to talk to work about taking time off, or you may feel worried about whether you’ll get sick pay. Get answers to your questions about work and a heart condition.

Find out about financial help you may be able to get from the government if you’re dealing with long-term ill health. You can also get free and impartial advice about managing your money from moneyhelper.org.uk and find out about benefits and other sources of financial support at turn2us.org.uk.

Exercise and myocarditis? 

Myocarditis can affect anyone, of any age and even people who were fit and healthy before. If you have myocarditis you will need time to rest and recover. Myocarditis can affect individuals differently, so you will need to get advice from your doctor on what’s best for you. Talk to your doctor about how long you should rest before re-starting exercise, and about types of exercise you can do safely. Generally, you are advised to avoid vigorous exercise for three to six months after you are diagnosed with myocarditis.

• Learn more about how to recover well. 

How to get support

Being diagnosed with myocarditis and living with myocarditis symptoms can feel overwhelming so we are here to help. To get support:

• Get in touch with our expert cardiac nurses - chat with them online, email or call 
• Ask your GP about getting talking therapy, or, if you’re in England, you can refer yourself for therapy through Improving Access to Psychological Therapies (IAPT)
• Speak to others with heart conditions by joining a support group or online community
• Sign up to our Heart Matters magazine and email newsletter, packed with health and recovery tips
• Join a Heart Support Group near you. 

You can trust our health information

We've followed an eight-step process to make sure this content is reliable, accurate and trustworthy. Learn how we make our health information reliable and easy to understand.

Page last reviewed: September 2022
Next review due: September 2025

Heart Helpline & other support:

• Call our Heart Helpline.
• Speak to others with heart conditions by joining a support group or online community.
• Sign up to our Heart Matters magazine and online information packed with health and lifestyle advice.