Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at April 26, 2016

Myocarditis occurs when the myocardium becomes inflamed. It is related to cardiomyopathy, or disease of the cardiac muscle. It has a variety of causes, including infections, allergic reactions, and autoimmune diseases.


Definition & Facts

The myocardium is located between the epicardium and endocardium. Together, these three layers make up the heart wall. When the middle layer, the myocardium, becomes inflamed for any reason, it is referred to as myocarditis.

As the thickest and most muscular layer of the heart wall, the myocardium takes on the bulk of responsibility for the muscle contractions that keep the heart pumping. When this middle lining of the heart wall becomes inflamed, it can compromise the heart's ability to continue pumping productively and functioning properly. It is estimated that 8 percent of heart transplants performed worldwide today are for myocarditis.

Symptoms & Complaints

Myocarditis can be difficult to diagnose because in the early stages it may be completely asymptomatic. The most commonly reported symptoms that are associated with myocarditis include:

The symptoms of myocarditis in children can be more sudden and severe, including difficulty breathing, rapid heart beat, and fainting. It is especially important to have any suspected cases of myocarditis in children promptly addressed. It is estimated that sudden death in young adults can be traced back to worsening myocarditis in up to 20 percent of cases.


Myocarditis is typically caused by viral infections. Viral infections that can cause it include HIV, herpes virus, coxsackie virus, and hepatitis C. Bacterial infections such as streptococcus and chlamydia may also cause myocarditis. Additionally, infections with fungi or parasites can also inflame the myocardium.

Exposure to environmental toxicants such as chemicals, certain medications, allergic reactions to certain illegal drugs like cocaine, or diseases (especially autoimmune diseases such as lupus) can also give rise to myocarditis.

Diagnosis & Tests

Diagnosis involves a patient's report of symptoms, a thorough medical history, and diagnostic tests. The tests most commonly performed include these:

  • X-ray of the chest. The doctor will be looking for visual details about the size, shape and function of the heart and the surrounding muscular wall.
  • Electrocardiogram. This test requires placement of non-invasive electrodes on the skin to measure heart activity.
  • Echocardiogram. This test uses sound waves to put together an electrical image of the heart.
  • MRI (magnetic resonance imaging) test. A cardiac MRI test can create a magnetic image of the heart using radio waves.
  • Heart biopsy. In fewer cases, a doctor may actually biopsy the heart to be sure of the diagnosis of myocarditis.
  • Blood tests. Testing the blood can measure for a number of important factors, including the production of recent viral antibodies, enzymes, and white blood cell and red blood cell counts.

Which test(s) and how many test(s) will depend on the treating physician and presenting symptoms, as well as the age and health of the patient.

Treatment & Therapy

The type of treatment and therapy prescribed will directly relate to the age and health of the patient as well as the severity of symptoms. If it has become clear there is an underlying cause (such as an autoimmune disease like lupus), the treatment generally focuses on treating that disease. Antibiotics may be prescribed to treat an underlying bacterial infection if it is deemed to be the cause of the myocarditis.

For symptoms that include shortness of breath, chest pain, heart arrhythmia, or heart failure, hospitalization and application of corticosteroids may be required. For a heart weakened by ongoing myocarditis, there are a number of medications that can be prescribed to lessen the heart's workload and give it time to heal. The most commonly prescribed medications include beta blockers, diuretics, (angiotensin converting enzyme inhibitors), ARBs (angiotensin II receptor blockers), and IV medications for severe symptoms requiring hospitalization.

Prevention & Prophylaxis

Because most cases of myocarditis can be traced back to exposure to a virus, the best prevention is to keep current with doctor-recommended health vaccines, adopt safe sex practices, steer clear of tick-infested areas and always practice good hand washing and personal hygiene. These preventative measures can lessen the likelihood one will be exposed to any viral, bacterial, parasitic or fungal triggers that could develop into myocarditis.