Myocarditis (Adult)

Myocarditis is inflammation of the heart muscle typically caused by the body’s reaction to a viral infection that reaches the heart. Bacteria, fungi, autoimmune disorders, environmental toxins and adverse reactions to medications can also cause myocarditis, which impairs the heart’s pumping function.

The normal heart is a four-chamber pump. The heart walls are made of muscle cells that respond to the heart’s electrical impulse by briskly contracting (shortening). Myocarditis causes swelling and damage of the heart muscle cells and thus impairs their ability to contract. If the damage is mild, the heart has enough reserve so that no symptoms occur. If severe, the heart is unable to pump enough blood to meet the body’s needs, resulting in symptoms of congestive heart failure.

Myocarditis can also be associated with abnormal heart rhythms such as atrial flutter, atrial fibrillation, heart block and ventricular tachycardia.

These symptoms can resolve, remain stable or become worse over time to the degree that a heart transplant is considered.


Possible symptoms of myocarditis include:

  • Palpitations (heart racing or "skipping" heart beats)
  • Chest pain or pressure
  • Low energy levels
  • Low exercise tolerance

Symptoms of congestive heart failure also include rapid breathing, clamminess or sweating, poor appetite and swelling around the eyes, hands and feet (more common in young adults).

If myocarditis has led to congestive heart failure, the heart rate and breathing rate are often accelerated. There may be a heart murmur (sound made by abnormal backward flow through the mitral valve) or other extra heart sounds, and the liver may be enlarged.


The most common test for myocarditis is an echocardiogram, which provides useful data about the severity of a patient’s condition. The diagnosis may be confirmed by a heart biopsy done during heart catheterization. If an infection is thought to be the cause of myocarditis, blood cultures or other special blood tests may be help identify the causative organism. Other tests include an electrocardiogram (ECG), Holter monitor and chest X-ray.


Myocarditis is typically treated with heart failure medications. Rest and a low-salt diet are also often recommended. If the cause is bacterial, antibiotics are used. A short course of steroids or other drugs that decrease the immune response may be used if the usual treatment is not helpful or if heart block occurs. Long-term therapy depends on the degree of residual heart damage and the presence of abnormal heart rhythms, which may require a pacemaker or defibrillator.

If there is severe heart damage that does not respond to treatment, a heart transplant may be necessary.

Make an Appointment

To schedule an appointment to discuss myocarditis or other cardiovascular conditions, call us at 888-287-1082 or visit our Make a Cardiovascular Appointment page, where you may fill out a Patient Appointment Request Form and view other information about scheduling a cardiovascular appointment.