Myocarditis: Symptoms, Causes, Treatment & Complications

Myocarditis is a condition involving inflammation of the heart muscle that can disrupt your heart's normal rhythm. This inflammation often leads to symptoms like chest pain, a rapid or irregular heartbeat, shortness of breath, or dizziness.

A viral infection like the flu or chickenpox is a common trigger, though serious bacterial or fungal infections can also be responsible. In some cases, myocarditis may result from autoimmune diseases that cause the body to attack its own healthy tissues.

Treatment is typically managed by a cardiologist and focuses on rest and medications tailored to the underlying cause of the inflammation. While many people recover at home, severe cases may require hospitalization to monitor and support heart function.

Main symptoms

The primary symptoms of myocarditis include:

• Chest pain;

• Rapid or irregular heartbeat;

• A feeling of tightness or pressure in the chest;

• Excessive fatigue;

• Difficulty breathing while resting or during physical activity;

• Shortness of breath;

• Swelling in the feet, ankles, and legs;

• Dizziness, lightheadedness, or fainting;

• Fever, in certain instances.

In some patients, myocarditis does not produce any noticeable signs or symptoms and is only discovered during routine cardiac testing.

However, if you experience chest pain or severe difficulty breathing, it is vital to seek emergency medical care immediately. An urgent evaluation is necessary to identify the cause of your symptoms and start the appropriate treatment plan.

Confirming a diagnosis

A cardiologist diagnoses myocarditis by reviewing your symptoms, medical history, and conducting a physical exam along with lab and imaging tests.

A physician may order a complete blood count (CBC), a C-reactive protein (CRP) test to check for inflammation, and a troponin test to measure cardiac markers.

Other diagnostic tools include chest X-rays, electrocardiograms (ECG/EKG), and echocardiograms to visualize how well the heart is functioning. The most definitive non-invasive diagnosis is typically achieved through a cardiac MRI.

Myocarditis vs. pericarditis

While both myocarditis and pericarditis involve inflammation of the heart, they affect different structures.

Myocarditis specifically targets the myocardium, which is the actual muscle of the heart. Pericarditis is the inflammation of the pericardium, the thin, sac-like membrane that surrounds and protects the heart.

Possible causes

The most frequent causes of myocarditis include:

• Viral infections: such as the flu, mononucleosis, chickenpox, hepatitis B or C, HIV, or COVID-19;

• Bacterial infections: including diphtheria, tuberculosis, or Lyme disease;

• Fungal infections: such as aspergillosis;

• Parasitic diseases: including Chagas disease or toxoplasmosis;

• Autoimmune diseases: such as systemic lupus erythematosus (lupus) or sarcoidosis;

• Cancer treatments: specifically chemotherapy drugs like doxorubicin or immunotherapy like interleukin-2;

• Medications: certain antibiotics, including penicillins or sulfonamides;

Myocarditis can affect individuals of any age. However, it is most frequently seen as a complication of viral infections that were not properly identified or managed.

Additionally, the risk is higher for individuals who struggle with substance or alcohol use disorders, those with existing autoimmune conditions, or those undergoing specific antibiotic or chemotherapy regimens.

Myocarditis and COVID-19

Myocarditis can occur as a complication of COVID-19. In some patients, the virus triggers an intense inflammatory immune response that may cause direct or indirect damage to the heart tissue.

Patients with COVID-19-related myocarditis may experience rapid breathing, persistent chest pain, and heart palpitations.

Treatment options

The treatment plan for myocarditis is guided by a cardiologist and is determined by the specific cause of the inflammation.

The standard treatments include:

1. Rest

Most recovery plans prioritize significant rest at home to reduce the workload on the heart muscle. Doctors typically recommend avoiding all strenuous physical activity and competitive sports for at least 3 to 6 months following an acute episode.

2. Medication

While antibiotics, antifungals, or antivirals do not treat the heart inflammation directly, they are used to clear the underlying infection. If the inflammation interferes with heart function, a cardiologist may prescribe heart medications to relax blood vessels, along with anti-inflammatories or pain relievers for chest discomfort.

3. ECMO

Extracorporeal membrane oxygenation (ECMO) is a specialized machine that acts as an external heart and lung. This life-support system maintains blood flow and oxygen levels in the body while the heart recovers from severe failure caused by inflammation.

4. Cardiac surgery

In advanced cases where heart function is severely compromised, surgical intervention may be necessary. This might include the placement of a Ventricular Assist Device (VAD) to help pump blood or an intra-aortic balloon pump to improve blood flow and reduce cardiac strain.

5. Heart transplant

In very rare and life-threatening scenarios where the heart does not recover, an emergency heart transplant may be the only remaining option.

Possible complications

In most instances, myocarditis resolves without leaving permanent damage, and many people may never even realize they had the condition.

However, severe inflammation can lead to permanent scarring of the heart muscle. This can result in long-term chronic conditions such as heart failure or secondary hypertension (high blood pressure).

In these situations, a cardiologist will prescribe a long-term medication regimen that may last several months or, in some cases, for the rest of the patient's life.