Myocarditis is a health condition that deserves attention. It is an inflammation of the heart muscle that can affect the heart’s ability to pump blood and maintain a regular heartbeat. The severity of the condition varies from person to person. In some cases, it may be mild and improve with appropriate medical care and follow-up, while in other cases, it may lead to complications requiring specialized medical attention.Myocarditis can occur as a result of certain infections, autoimmune diseases, or other factors and causes. Therefore, recognizing the symptoms early and undergoing the appropriate medical tests can help ensure an accurate diagnosis and the timely initiation of suitable treatment.In this article on Dalili Medical, we will discuss the causes of myocarditis, its symptoms, diagnostic methods, treatment options including medications and medical procedures, prevention methods, and the most frequently asked questions about the condition.

What Is Myocarditis?

Myocarditis is a medical condition characterized by inflammation of the heart muscle tissue. This inflammation may affect the heart’s ability to pump blood efficiently or maintain a regular heartbeat. The severity of the condition varies from one case to another. It may be mild and improve with appropriate medical follow-up and treatment, while severe cases may lead to complications requiring specialized medical care.

Is Myocarditis Dangerous?

The severity of myocarditis depends on the extent of inflammation and how much it affects heart function. Some cases may be mild, while more severe cases can lead to weakened heart muscle or abnormal heart rhythms. Therefore, early diagnosis and regular medical follow-up are recommended.

Can Myocarditis Be Treated?

Yes, myocarditis can be treated. Treatment depends on the underlying cause, the severity of the condition, and the extent to which heart function is affected. Some mild cases may only require rest and medical monitoring, while other cases may require medications to treat heart failure or abnormal heart rhythms. In severe cases, advanced therapies may be needed to support heart function.

Does Myocarditis Require Surgery?

In most cases, myocarditis does not require surgery. Treatment primarily focuses on addressing the underlying cause, managing complications, and supporting heart function. However, certain interventional or surgical procedures may be considered in severe cases or when specific complications occur, such as acute heart failure or certain dangerous heart rhythm disorders.

Can You Exercise With Myocarditis?

People with myocarditis are generally advised to avoid intense exercise and strenuous physical activity during the active phase of the condition to reduce the risk of cardiac complications. A gradual return to physical activity should only take place after evaluation by a cardiologist and confirmation that heart function has stabilized.

Is Myocarditis Contagious?

Myocarditis itself is not contagious and cannot be transmitted from one person to another. However, myocarditis may sometimes develop as a result of an infection, and the underlying infection may be contagious depending on its type and how it spreads.

Can Myocarditis Be Completely Cured?

Yes, many people with myocarditis can recover completely, particularly when the condition is diagnosed early and appropriate treatment and follow-up are provided. Recovery time varies from person to person depending on the cause and severity of the inflammation and the extent of heart involvement. Some patients may require longer-term medical follow-up if heart muscle weakness or other complications persist.

Can Myocarditis Return After Recovery?

Myocarditis can recur in some people, although this does not necessarily happen in every case. The likelihood of recurrence depends on the underlying cause, the person’s health condition, and their response to treatment and medical follow-up.

Causes of Myocarditis

Myocarditis is inflammation of the heart muscle that may affect the heart’s ability to pump blood effectively or maintain a regular heartbeat. In many cases, doctors are unable to identify the exact cause. However, several known causes and factors may be associated with the development of myocarditis.

Main Causes of Myocarditis

1. Viral Infections – One of the Most Common Causes

Certain viral infections are recognized causes of myocarditis. Inflammation may develop during or after an infection as a result of the body’s immune response.

Viruses that have been associated with myocarditis include:

• Adenoviruses.
• Enteroviruses, including Coxsackievirus.
• Epstein–Barr virus (EBV).
• Herpes simplex virus.
• Parvovirus B19.
• Hepatitis B and C viruses.
• Human immunodeficiency virus (HIV).
• SARS-CoV-2, the virus that causes COVID-19.

Having one of these viral infections does not necessarily mean that myocarditis will develop. Myocarditis remains an uncommon complication compared with the overall number of viral infections.

2. Bacterial Infections

Certain bacterial infections may, in some cases, lead to myocarditis, including infections caused by some types of Staphylococcus and Streptococcus bacteria.

Myocarditis may also be associated with less common bacterial infections, such as Lyme disease, depending on the type and severity of the infection and its effects on the body.

3. Fungal or Parasitic Infections

These causes are less common but can lead to myocarditis, particularly in people with weakened immune systems or severe systemic infections.

Certain fungi and parasites may reach the heart tissues and cause inflammation or injury to the heart muscle.

4. Autoimmune Diseases

In some autoimmune diseases, the immune system mistakenly attacks the body’s own tissues, and this immune response may involve the heart muscle.

Examples of conditions that may be associated with myocarditis include:

• Systemic lupus erythematosus (SLE).
• Certain types of vasculitis.
• Giant cell arteritis.
• Takayasu arteritis.
• Certain connective tissue diseases.

In these cases, myocarditis may be part of a broader inflammatory or autoimmune condition affecting multiple organs rather than an isolated heart problem.

5. Certain Medications

In rare cases, myocarditis may develop as a result of an inflammatory or immune reaction to certain medications.

Medications that have been associated with myocarditis in some medical reports include:

• Certain cancer treatments.
• Some antibiotics, including certain penicillins and sulfonamides.
• Some medications used to treat seizures.

This does not mean that these medications commonly cause myocarditis. Rather, it may occur as a rare adverse effect depending on the specific medication and the individual’s health condition.

6. Certain Cancer Immunotherapies

Immune checkpoint inhibitors, which are used to treat certain types of cancer, can rarely trigger an immune response that leads to myocarditis.

This type of myocarditis can be serious. Therefore, people receiving these treatments require careful medical monitoring, particularly if they develop symptoms such as chest pain, shortness of breath, or palpitations.

7. Toxic Substances and Chemical Exposure

Certain toxic substances can affect the heart muscle and cause injury or inflammation. Examples include:

• Carbon monoxide.
• Certain toxic chemicals.
• Some cases of drug poisoning or systemic toxicity.

Radiation therapy may also be associated with heart injury under certain circumstances, particularly when radiation is used to treat cancers in areas close to the heart.

8. Myocarditis After Certain COVID-19 Vaccines

Rare cases of myocarditis have been reported after some mRNA COVID-19 vaccines, with cases observed more frequently among adolescent and young adult males, often within a short period following vaccination.

At the same time, COVID-19 infection itself can be associated with cardiac complications, including myocarditis. Therefore, the benefits and risks of vaccination or infection should be assessed according to age, health status, and current medical recommendations rather than considering vaccination a common cause of myocarditis.

9. Rare and Severe Inflammatory Types

There are rare forms of myocarditis that can be particularly severe, including:

• Giant-cell myocarditis.
• Eosinophilic myocarditis.
• Certain severe forms of immune-mediated myocarditis.

These conditions require prompt specialized evaluation because some can cause rapid deterioration in heart function.

Can the Cause of Myocarditis Be Identified in Every Case?

No. In some patients, the exact cause cannot be clearly identified even after appropriate investigations. Identifying the underlying cause depends on the medical history, physical examination, blood tests, electrocardiogram (ECG), echocardiogram, cardiac magnetic resonance imaging (MRI), and, in selected cases, a heart muscle biopsy when medically indicated.

It is also important to note that having a risk factor or a previous infection does not necessarily mean that a person will develop myocarditis. The causes and underlying mechanisms can vary from one case to another.

Why Does Myocarditis Occur?

The virus or bacteria does not necessarily have to directly attack the heart muscle. In some cases, an infection occurs first, followed by a strong or abnormal immune response that causes inflammation and damage to heart muscle cells. Therefore, myocarditis may develop during an infection or shortly after recovery from it.

Can the Cause of Myocarditis Always Be Identified?

Not always. In many cases, doctors are unable to determine a clear cause of the inflammation, even after the necessary medical tests have been performed. In such cases, the condition may be referred to as idiopathic myocarditis.

When Does Myocarditis Become a Medical Emergency?

Unexplained chest pain, shortness of breath, fainting, or severe or irregular palpitations—especially following a recent infection or when accompanied by other symptoms—require prompt medical evaluation.

This is because myocarditis can affect the heart’s ability to pump blood and may also cause abnormal heart rhythms. In severe cases, it can lead to heart failure.

Symptoms of Myocarditis

Myocarditis is inflammation of the heart muscle tissue that may affect the heart’s ability to pump blood or cause abnormal heart rhythms. Symptoms can vary considerably from one person to another. The inflammation may be mild and cause few or no noticeable symptoms, while some cases can cause more severe symptoms.

1. Chest Pain or Discomfort

Chest pain is a common symptom and may present as:

• Pain, pressure, or discomfort in the chest.
• Persistent or intermittent pain.
• Pain that occurs at rest or during physical activity.
• Pain that may begin several days or about a week after a viral infection.

Important: Chest pain caused by myocarditis can resemble pain associated with other heart conditions. Therefore, the nature of the pain alone cannot determine its cause.

2. Shortness of Breath

Shortness of breath may occur:

• During mild physical activity.
• While walking or exercising.
• In more severe cases, even while resting.

This may occur when inflammation affects the heart’s ability to pump blood efficiently.

3. Heart Palpitations and Abnormal Heart Rhythms

A person may feel that their heart:

• Is beating rapidly.
• Is fluttering or pounding unusually.
• Is beating more forcefully than usual.
• Seems to pause briefly and then resume.
• Is beating irregularly.

This can occur because myocarditis may affect the heart’s electrical system, potentially leading to abnormal heart rhythms.

4. Fatigue and Weakness

A person may experience unusual tiredness or a noticeable decrease in their ability to perform normal daily activities, particularly when the heart’s pumping efficiency is affected.

5. Dizziness or Feeling Faint

Dizziness or a feeling of being about to faint may occur, particularly when abnormal heart rhythms or reduced cardiac output are present.

6. Fainting

Fainting does not occur in every case, but it may develop, particularly in the presence of certain heart rhythm abnormalities.

Fainting is especially concerning when it occurs together with palpitations, chest pain, or shortness of breath, as this requires prompt medical evaluation.

7. Flu-Like or Infection-Related Symptoms

General symptoms resembling an infection may occur before or alongside the heart-related symptoms, including:

• Fever.
• Sore throat.
• Headache.
• Body aches.
• Joint pain.
• General fatigue and feeling unwell.

These symptoms may occur after a viral infection.

8. Swelling of the Legs, Ankles, or Feet

Swelling may occur in:

• The feet.
• The ankles.
• The legs.

These symptoms are more concerning when they occur together with shortness of breath or increased fatigue, as they may indicate impaired heart function.

9. More Severe Symptoms When the Heart Muscle Is Weakened

In severe cases, myocarditis may reduce the heart’s ability to pump blood effectively, resulting in symptoms associated with heart failure, such as:

• Severe shortness of breath.
• Swelling of the limbs.
• Severe fatigue.
• Reduced ability to perform normal activities.

Symptoms of Myocarditis in Children and Adolescents

Myocarditis may appear in children and adolescents as:

• Difficulty breathing.
• Rapid breathing.
• Chest pain.
• Rapid or irregular heartbeat.
• Fainting.
• Fever.

Unusual heart-related symptoms in children and adolescents require appropriate medical evaluation, particularly when they are severe or develop suddenly.

Can Myocarditis Occur Without Symptoms?

Yes. Some people may not experience noticeable symptoms, particularly during the early stages, or their symptoms may be very mild. Therefore, the absence of severe symptoms does not completely rule out myocarditis.

When Does Myocarditis Require Emergency Care?

Emergency medical care should be sought if any of the following occur:

• Unexplained chest pain.
• Significant or severe shortness of breath.
• Severe or unusually rapid palpitations.
• Fainting.
• A combination of more than one of these symptoms, especially following a recent infection.

This is because the symptoms of myocarditis can resemble those of other medical emergencies involving the heart, and the underlying cause cannot be determined based on symptoms alone.

How Is Myocarditis Diagnosed?

Symptoms alone are not enough to diagnose myocarditis. Depending on the individual case, the doctor may recommend several tests, including:

• Electrocardiogram (ECG).
• Blood tests, including troponin testing.
• Echocardiogram (Echo).
• Cardiac magnetic resonance imaging (Cardiac MRI) in some cases.

The doctor determines which tests are appropriate based on the symptoms, physical examination, medical history, and the results of the initial investigations.

Diagnosis of Myocarditis

The diagnosis of myocarditis is based on a combination of information, including symptoms, medical history, physical examination, and the results of several medical tests. There is no single test that can definitively confirm or rule out myocarditis on its own.

1. Symptoms and Medical History

The doctor begins by evaluating the symptoms and reviewing the patient’s medical history. They may ask about:

• Chest pain or pressure.
• Shortness of breath, especially during physical activity or when lying down.
• Heart palpitations or irregular heartbeats.
• Dizziness or fainting.
• Unusual fatigue and reduced exercise tolerance.
• Fever or a recent infection, such as a sore throat or viral infection symptoms.
• Autoimmune diseases or the use of certain medications that may be associated with myocarditis.

2. Physical Examination

The doctor performs a comprehensive physical examination, which may include:

• Measuring blood pressure.
• Measuring heart rate.
• Checking blood oxygen levels.
• Measuring body temperature.
• Listening to the heart and lungs.
• Looking for signs of fluid retention, such as swelling in the legs and ankles.

These findings help assess the condition of the heart and determine how the inflammation may be affecting its function.

3. Electrocardiogram (ECG)

An electrocardiogram is used to detect electrical changes in the heart. It may show:

• Abnormal heart rhythms.
• Changes in the ECG waves or segments.
• Abnormalities in the heart’s electrical conduction.

However, a normal ECG does not definitively rule out myocarditis. Therefore, ECG findings must be interpreted alongside the symptoms and other test results.

4. Troponin Test

Troponin is one of the most important blood tests when heart muscle injury is suspected.

An elevated troponin level indicates injury or damage to heart muscle cells. This can occur in myocarditis, but troponin can also be elevated due to other conditions. Therefore, an elevated troponin level alone is not enough to confirm a diagnosis of myocarditis.

The doctor may also order additional blood tests, such as:

• Complete blood count (CBC).
• C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) as markers of inflammation.
• Kidney and liver function tests.
• Blood electrolyte levels.
• BNP or NT-proBNP when reduced heart function or heart failure is suspected.

5. Echocardiogram

An echocardiogram, commonly known as an echo, uses ultrasound waves to assess the structure and function of the heart.

It can help evaluate:

• The heart’s pumping strength, including the ejection fraction (EF).
• Movement of the heart walls.
• The size of the heart chambers.
• The presence of fluid around the heart.
• Signs of reduced heart function or heart failure.

An echocardiogram may be normal in some mild cases, so a normal result does not always rule out myocarditis.

6. Cardiac Magnetic Resonance Imaging (Cardiac MRI)

Cardiac MRI is one of the most important imaging techniques used when myocarditis is suspected. It provides detailed information about the heart muscle tissue.

It may help detect:

• Inflammation or swelling of the heart muscle.
• Injury to heart muscle tissue.
• Areas of fibrosis or tissue damage.
• Patterns of heart muscle injury that can help doctors distinguish myocarditis from other causes of elevated troponin levels.

Doctors may use established imaging criteria, including the updated Lake Louise criteria, when interpreting cardiac MRI findings in suspected cases.

7. Evaluation of the Coronary Arteries

When chest pain and elevated troponin levels are present, the doctor may need to rule out coronary artery blockage or a heart attack, particularly when the symptoms and risk factors make these possibilities relevant.

The coronary arteries may be evaluated using:

• Cardiac catheterization and coronary angiography.
• Coronary computed tomography angiography (CCTA).

The doctor determines the most appropriate method based on the clinical condition and level of suspicion.

8. Heart Rhythm Monitoring

When palpitations, fainting, or suspected abnormal heart rhythms are present, the patient may need heart rhythm monitoring for an appropriate period.

Methods may include:

• A Holter monitor to record the heart rhythm for 24–48 hours or longer, depending on the situation.
• Continuous cardiac monitoring in the hospital when necessary.

This monitoring can help detect abnormal heart rhythms that may not appear during a short ECG recording.

9. Endomyocardial Biopsy

An endomyocardial biopsy is a procedure in which a small sample of heart muscle tissue is removed and examined under a microscope.

It is not a routine test for everyone suspected of having myocarditis. However, it may be useful in selected cases, particularly when:

• The condition is severe or rapidly worsening.
• The doctor needs to identify a specific type of myocarditis.
• Biopsy results are necessary to guide treatment or make important therapeutic decisions.

Surgical and Interventional Treatment of Myocarditis

In most cases of myocarditis, surgery is not the primary treatment. Management generally focuses on medications, supportive care, and monitoring heart function.

However, some patients may require interventional or surgical procedures when severe complications develop, such as acute heart failure, dangerous heart rhythm abnormalities, or severe deterioration in heart function.

Main Procedures Used

1. Endomyocardial Biopsy

An endomyocardial biopsy is not a treatment for inflammation. Rather, it is a diagnostic procedure used in selected cases when determining the type or cause of inflammation is important for choosing the appropriate treatment.

The procedure generally involves:

1. Inserting a thin catheter through one of the large veins.
2. Guiding the catheter into the heart.
3. Taking very small samples of heart muscle tissue using a specialized instrument.
4. Sending the samples to a laboratory for examination to determine the nature of the injury.

A biopsy is not performed in every patient with myocarditis. The doctor determines whether it is necessary based on the severity of the condition and the expected benefits of the procedure.

2. Mechanical Circulatory Support in Severe Cases

If myocarditis causes severe acute heart failure and a major reduction in the heart’s ability to pump blood, the patient may require temporary mechanical support for circulation.

Among the main options are:

Extracorporeal Membrane Oxygenation (ECMO)

ECMO may be used in certain critical cases to support circulation and, depending on the type of ECMO system and the patient’s condition, may also provide respiratory support.

It is used as a temporary supportive measure rather than a direct treatment for the inflammation itself, allowing time for the heart to recover or for another treatment strategy to be implemented.

Ventricular Assist Devices (VADs)

These devices help pump blood when one or both ventricles have severely reduced function.

They may be used in selected cases as temporary support while the heart recovers or as part of another treatment strategy determined by a specialized cardiac team.

3. Heart Transplantation

In a very small proportion of cases, myocarditis may lead to severe and persistent heart failure that does not respond to available treatments.

In such situations, after a comprehensive evaluation, heart transplantation may become a treatment option.

The transplant procedure generally involves:

1. Removing the heart that can no longer function adequately.
2. Implanting the donor heart.
3. Connecting the new heart to the major blood vessels.
4. Using immunosuppressive medications after transplantation to reduce the risk of rejection.

Heart transplantation is a complex procedure and is reserved for highly selected cases following evaluation at a specialized medical center.

4. Procedures for Treating Heart Rhythm Disorders

Myocarditis can cause abnormal heart rhythms, and some cases may require specialized procedures, such as:

Electrical Cardioversion

Electrical cardioversion may be used for certain types of abnormal heart rhythms to restore a normal heart rhythm.

Catheter Ablation

Catheter ablation may be used to treat certain specific heart rhythm disorders. A catheter is guided into the heart to target the area responsible for the abnormal electrical activity.

Pacemaker

Some patients may require a pacemaker when severe and persistent electrical conduction problems cause dangerously slow heartbeats.

Implantable Cardioverter-Defibrillator (ICD)

An ICD may be considered in selected cases when there is an ongoing risk of dangerous ventricular arrhythmias that could be life-threatening. The doctor determines whether an ICD is appropriate based on the patient’s condition and the persistence of the risk.

Is the Inflamed Part of the Heart Muscle Surgically Removed?

Usually, no.

There is no routine surgery in which the heart is opened and the inflamed portion of the heart muscle is removed. This is because myocarditis affects the heart muscle tissue itself. Treatment therefore focuses on:

• Treating the underlying cause when it is known and treatable.
• Supporting heart function.
• Treating heart failure when present.
• Controlling abnormal heart rhythms.
• Monitoring the patient and detecting complications early.

In severe cases, the patient may require supportive or interventional procedures, but these procedures are not intended to surgically remove the inflammation.

When Does Myocarditis Become an Emergency?

When myocarditis is suspected, severe symptoms such as:

• Severe or unexplained chest pain.
• Significant or severe shortness of breath.
• Fainting.
• Severe palpitations or obvious abnormal heart rhythms.
• Bluish discoloration of the skin or lips.
• Rapid deterioration in the general condition.

require urgent medical evaluation. Severe cases can significantly impair heart function and circulation and may require hospitalization, continuous monitoring, and possibly advanced mechanical support.