Viral Myocarditis: Symptoms, Causes & Treatment

Viral myocarditis is inflammation of the heart muscle (the muscular tissue responsible for pumping blood), and its most common cause is viral infection. When the body is infected with a certain virus, the virus or the immune response to it may directly attack the heart-muscle cells, causing inflammation that weakens the heart's ability to contract and pump efficiently.

The disease's severity varies greatly: some cases are very mild and may pass without clear symptoms and resolve on their own, while others are severe and lead to acute heart dysfunction (heart failure) or serious heart-rhythm disturbances. Symptoms often appear days to weeks after a viral infection (respiratory or digestive) and include chest pain or pressure, shortness of breath on exertion or at rest, palpitations and a fast heart rate, unusual fatigue, and sometimes leg swelling or fainting.

Myocarditis is an important cause of heart problems in healthy young people and sometimes of sudden cardiac death, so noting cardiac symptoms after a viral infection is important. Diagnosis relies on an electrocardiogram, cardiac-enzyme tests, echocardiography, and sometimes cardiac MRI. Treatment varies by severity: mild cases need rest, monitoring, and avoiding strenuous exertion and sports for a period, while severe cases need hospital care and medications to support the heart and treat rhythm disturbance and heart failure. Early detection and treatment improve outcomes, and most mild cases recover well.

• Chest pain or pressure.
• Shortness of breath on exertion or at rest.
• Palpitations and a fast or irregular heartbeat.
• Unusual fatigue and leg swelling.
• Fainting in severe cases.

• Viral infection (the most common cause).
• The virus or the immune response attacking heart-muscle cells.
• Less common causes: bacteria, immune diseases, some medications and toxins.

• Electrocardiogram and cardiac-enzyme tests.
• Echocardiography to assess pumping function.
• Cardiac MRI and sometimes a biopsy in selected cases.

Mild cases

• Rest and avoiding strenuous exertion and sports for a period with monitoring; many recover on their own.

Severe cases

• Hospital care and medications to support the heart and treat heart failure and rhythm disturbance.
• Support devices or advanced procedures in critical cases.

This content is educational and does not replace consulting a cardiologist.

• Heart failure and weakened pumping function.
• Serious heart-rhythm disturbances.
• Clots or chronic cardiomyopathy, and rarely sudden cardiac death.

• Preventing viral infections (hygiene, vaccinations).
• Rest and avoiding strenuous sports during viral infection and recovery.
• Noting cardiac symptoms after infection and seeing a doctor.