Myopericarditis is a term that describes two distinct heart conditions that occur simultaneously, and are usually the result of a viral infection. One condition involves the pericardium, the thin, but protective sac-like membrane surrounding your heart. The other affects the myocardium, the thickest inner layer of your heart muscle itself.

Symptoms can range from very minor chest pain to more serious injuries to your heart. For people with severe cases, heart failure may result. But treatment that includes anti-inflammatory medications is often sufficient to prevent long-term complications from myopericarditis.

In this article, we take a closer look at myopericarditis, including symptoms, diagnosis, treatment, and outlook for people with it.

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Myopericarditis is a complication of pericarditis. It’s characterized by acute inflammation of the myocardium. Medical illustration by Bailey Mariner

If you have myopericarditis, it means you have a complication of pericarditis. Pericarditis is the inflammation of the pericardium, the thin sac that surrounds and protects your heart.

Instead of the inflammation being contained to your pericardium, myopericarditis indicates that the inflammation and irritation has extended down to the thick layer of your heart muscle called the myocardium.

Related conditions

Myopericarditis is one of several similar-sounding conditions that affect your heart. Others include:

  • Myocarditis: This is inflammation of your heart wall’s middle layer, usually brought on by a viral infection.
  • Pericarditis: This is irritation of the pericardium, the thin membrane that surrounds your heart. It’s also usually triggered by a viral infection.
  • Perimyocarditis: This is inflammation of your pericardium and the myocardium beneath it, usually associated with a viral infection.

Because a viral infection is often the trigger for myopericarditis, early symptoms may include typical flu-like symptoms, such as a low-grade fever or congestion.

But once your pericardium is involved, a sharp chest pain is likely to develop. Coughing or deeply inhaling may make it worse.

If inflammation affects your myocardium, the pain may be constant and similar to that of angina. Angina is a type of chest pain caused by the reduction in blood flow to your heart muscle. It’s typically associated with coronary artery disease.

For people with serious cases, symptoms may include shortness of breath and fatigue.

A 2015 article suggests that a viral infection — typically coxsackievirus — is the usual cause of myopericarditis. Bacterial and fungal infections may also trigger myopericarditis. For some people, myopericarditis can occur for unknown (idiopathic) reasons.

Other risk factors include conditions that can raise inflammation in your heart, including:

If myopericarditis is diagnosed early and monitored closely, it’s often possible to avoid serious complications.

But for people with severe cases, the buildup of fluid within their pericardium can result in a condition called pericardial effusion. This can put a burden on your heart function, possibly weakening it to the point where heart failure results.

Heart failure may also develop if your myopericarditis lasts for a long time, allowing scarring and damage to occur to your pericardium. This condition is called constrictive pericarditis.

If heart failure develops, it can be fatal. Medications and implantable devices can help promote better heart function, but heart failure is a serious complication that hampers daily functioning and quality of life.

Arrhythmias are another potential complication that can occur when the function of your heart is weakened. Arrhythmias can be life threatening, particularly if they interfere with blood flow to your body and vital organs.

Lab tests and cardiac imaging are used to diagnose myopericarditis and rule out other, similar heart conditions.

Blood test results associated with myopericarditis may reveal elevated levels of:

Standard imaging tests may be helpful too. Myopericarditis may lead to certain heart rhythm changes that can be identified in an electrocardiogram. And a chest X-ray may reveal the buildup of fluid in your pericardium. An echocardiogram isn’t always helpful, as an individual with myopericarditis may still have normal heart function.

One of the most useful screenings is cardiac magnetic resonance (CMR) imaging. CMR imaging uses magnetic fields and radio waves to produce images of your internal organs.

CMR can usually illustrate the degree to which your myocardium and pericardium are affected by myopericarditis. And it can show whether the condition has affected the pumping ability of the heart.

Myopericarditis is usually treatable, with full recovery being likely. This is especially true if you receive a diagnosis early and you follow a doctor or other healthcare professional’s advice about treatment and follow-up appointments.

If your left ventricle, which pumps blood out to the rest of your body, continues to function normally, then the use of nonsteroidal anti-inflammatory drugs (NSAIDs) is recommended as the first-line treatment.

If your myocardium is greatly affected, however, a doctor may prescribe low doses of NSAIDS, as these medications could negatively impact myocardial function.

Other anti-inflammatory drugs, such as colchicine and corticosteroids, may also be helpful. If a doctor determines that a bacterial infection caused your heart complications, then antibiotics may be necessary.

You should also plan to rest and restrict certain activities, such as those involving physical exertion, for several weeks, especially if there’s significant myocardial involvement.

For an otherwise healthy person, a bout of myopericarditis is unlikely to cause permanent heart problems.

A 2020 article suggests that the outlook for people with myopericarditis is much like that for acute pericarditis. That means you can expect a good long-term outcome if there are no other cardiac complications.

If the myopericarditis becomes chronic, however, you may need to have the pericardium removed surgically. Even in these cases, the majority of people make a full recovery.

It’s important to know that if you have a cardiovascular disease or other cardiac condition, myopericarditis may be more challenging to manage. But if treated promptly and you give yourself time to rest and recover from whatever infection might’ve caused myopericarditis, you should expect a good outcome.

Can myopericarditis be prevented?

There’s no vaccine or other specific preventive measure you can take to avoid myopericarditis. But as much as possible, try to avoid viral infections, such as influenza and coronavirus disease 19 (COVID-19), as well as bacterial and fungal infections.

Because heart disease also raises your risk of myopericarditis, work closely with a cardiologist (a doctor who specializes in disorders of the heart) to manage your heart health.

Can COVID-19 cause myopericarditis?

Myopericarditis and myocarditis have been associated with COVID-19. A 2020 study notes that myopericarditis is considered a documented heart-related complication of the virus, with an estimated 7% of people with COVID-19 experiencing some inflammation or irritation of the myocardium.

Can the COVID-19 vaccine cause myopericarditis?

From the first few months of the COVID-19 vaccine rollout, concerns started to grow about a connection between the new vaccines and myopericarditis and myocarditis.

Several studies, including a 2021 Danish study suggest that the vaccination with a messenger RNA (mRNA)-1273 is associated with a much higher risk of developing either of the two conditions, especially among people under the age of 40 years. All of the people in these studies who developed myopericarditis or myocarditis following an mRNA vaccination recovered.

What’s the difference between myopericarditis and endocarditis?

While myopericarditis involves your pericardium and myocardium, endocarditis is an inflammation of your heart chambers’ inner lining and the valves of your heart.

Endocarditis is much more likely to be a life threatening condition. This is especially true for people already coping with valve disease or who have an artificial valve.

While any health problem involving the heart is concerning, myopericarditis is usually treatable and not likely to cause long-term complications.

Usually brought on by a viral infection, myopericarditis can cause inflammation of the pericardium (the membrane that surrounds your heart) and the myocardium (one of the inner layers of your heart muscle wall).

By following the recommendations of a cardiologist and taking steps to avoid infections, you should be able to keep your heart healthy and recover from this inflammatory, but manageable, condition.