Myocarditis

What is myocarditis? 

Myocarditis is inflammation of the heart muscle, also known as the myocardium. When the heart muscle becomes inflamed, it can affect the heart’s ability to pump blood effectively and may disrupt its normal electrical rhythm.

It can range in severity from mild cases that resolve on their own to more serious presentations that may require specialist management. In rare cases, severe myocarditis can lead to heart failure or life-threatening arrhythmias, which is why prompt medical assessment and diagnosis are important.

Myocarditis is considered a rare disease, but it is more common than people may realise. It can affect those of all ages, including healthy, active individuals. In younger people and athletes, it is one of the more commonly identified cardiac causes of symptoms such as chest pain and palpitations, during or after a viral illness.

Symptoms  

Symptoms of myocarditis can vary considerably between individuals. Some people may experience significant symptoms, while others may only have mild or no noticeable symptoms at all, making the condition easy to miss without specialist assessment.

Common symptoms can include:

• Chest pain or tightness, which may be sharp or pressure-like
• Shortness of breath, particularly with exertion or when lying flat
• Palpitations, the feeling that your heart is fluttering, racing or pounding
• Fatigue and a general feeling of being unwell
• Swelling in the legs, ankles or feet
• Dizziness or light-headedness
• Flu-like symptoms such as fever, muscle aches and joint pain, particularly in the early stages

Symptoms often develop in the days or weeks following a viral infection. If you notice new cardiac symptoms, such as chest pain or breathlessness, during or shortly after a viral illness, you should seek medical assessment rather than thinking these symptoms are part of the viral illness itself.

If you experience sudden chest pain, shortness of breath, loss of consciousness or a very fast or irregular heartbeat that does not settle, call 999 immediately for emergency medical attention.

Causes  

Myocarditis is most commonly caused by a viral infection, and sometimes it can follow a relatively mild illness.

Common causes include:

• Viral infections: Particularly enteroviruses such as coxsackievirus, as well as influenza, COVID-19 and other respiratory viruses.
• Other infections: Bacterial, fungal and parasitic infections can also cause myocarditis, though this is less common.
• Autoimmune conditions: Some autoimmune conditions, such as lupus, rheumatoid arthritis and sarcoidosis, can cause the immune system to attack heart tissue and lead to myocarditis.
• Illicit substances or drugs can trigger myocarditis
• Hypersensitivity reactions: Having an immune reaction to medications such as antibiotics, diuretics or anti-inflammatory drugs.

In some cases, no clear cause is found, and this is known as idiopathic myocarditis. The condition is not caused by an unhealthy lifestyle, but certain lifestyle factors might put your immune system under strain, including chronic stress, poor sleep and overtraining in athletes. This can affect how the body responds to infection.

Diagnosis  

Diagnosing myocarditis requires a thorough clinical assessment and targeted investigations.

During your initial appointment, we assess your symptoms and evaluate your medical and lifestyle history. This will help us understand the timeline of your symptoms, any recent illness, your overall health and lifestyle habits. This may also involve a physical examination to get a better understanding of your heart health.

If we suspect myocarditis, we will investigate further to confirm the diagnosis and determine the cause. Some initial tests we may perform can include blood tests, an electrocardiogram (ECG) or an echocardiogram. We may also recommend a heart MRI scan to detect any inflammation, swelling and scarring of the heart muscle. This is often a key investigation in the diagnostic process of myocarditis.

We may suggest further investigations depending on your symptoms and history. At Cardiologist London, we are here to support you through every step of your journey.

Treatment  

Most people with mild to moderate myocarditis can make a full recovery, especially when the condition is identified and managed early.

If we have determined that you have myocarditis, we will discuss the treatment options with you based on your personal circumstances and needs. Treatment for myocarditis will depend on the severity of your condition and the underlying cause. This may include rest, medication, lifestyle changes, monitoring and follow-up.

Rest and activity modification  

Rest is one of the most important parts of the early management of myocarditis. Physical activity, including exercise and sport, is typically restricted during the active phase of this condition. Continuing to exercise while the heart muscle is inflamed may worsen your condition and can increase the risk of developing serious arrhythmias (abnormal heart rhythms).

We will advise you on when it is safe to gradually return to exercise based on your clinical picture and investigations.

Medication 

Depending on your symptoms, the severity of your condition and how your heart is functioning, medication may be recommended to support your recovery. This may include:

• Anti-inflammatory medication, in selected cases to help reduce inflammation in the heart muscle
• Medications to support heart function, such as beta-blockers or ACE inhibitors
• Anti-arrhythmic medication if you are experiencing abnormal heart rhythms
• Treatment of the underlying cause, for example, if the myocarditis is linked to an autoimmune condition or other identifiable cause.

Monitoring and follow-up  

Follow-up assessments are an essential part of managing myocarditis. You may need repeat investigations to help us to track your recovery, confirm when inflammation has resolved, and guide decisions around returning to normal activities and sport.  

Our integrative cardiology approach  

At Cardiologist London, we have a personalised, thorough approach to the assessment and management of myocarditis. Your treatment and recovery plan will be built around your individual circumstances, symptoms and lifestyle.

As an Integrative Cardiologist, my approach goes beyond managing the immediate episode. I will review your heart health holistically, including the factors that may have contributed to your condition and those that can support your recovery. This includes:

• Sleep: Quality sleep is essential to immune recovery and cardiac healing. Having good quality sleep will form part of your recovery plan.
• Stress: Chronic stress can suppress immune function and affect the body’s ability to recover. Read our article to learn more about stress management techniques: How mind-body practices can help reduce stress and support heart health.
• Nutrition can play a role in immune recovery. We can provide personalised dietary guidance to support your treatment and heart health.
• Exercise planning and return to sport: We will work together to ensure a safe, structured and monitored return to full physical activity based on your condition, medical history and overall health. We offer additional guidance for athletes on how they safely return to sport.
• Long-term cardiac risk: If myocarditis has caused scarring or ongoing changes to the heart muscle, we will discuss what this might mean for your future heart health and how you can manage your risk going forward.

We also offer a Health MOT for patients who may want a comprehensive baseline assessment for their heart health once the myocarditis has resolved. This can help us assess if your heart has fully recovered and provide you with peace of mind for your future.