Infectious myocarditis is a rare inflammation of the muscle of the heart (myocardium) usually caused by a viral infection, such as adenovirus, hepatitis B and C, parvovirus, or herpes simplex; a bacterial infection, such as staphylococcus, streptococcus, or Lyme disease; a parasitic infection, such as toxoplasma or Chagas disease; or a fungal infection, such as Candida albicans or other fungi.

Symptoms of infectious myocarditis depend on whether the disease is mild or severe. Patients with mild myocarditis may not have any symptoms, or only shortness of breath or chest pain. Symptoms of more severe infectious myocarditis may include fatigue, headache, body aches, joint pain, fever, sore throat, diarrhea, chest pain, abnormal heart rhythms (arrhythmias), shortness of breath, ankle swelling (edema), blood clots in the heart, heart failure, stroke, heart attack, loss of consciousness, or sudden death.

Treatment for infectious myocarditis depends on the cause. Some patients with infectious myocarditis may not need any treatment. Treatment for mild infectious myocarditis involves avoiding strenuous activity or sports for three to six months and bedrest. Other treatments for myocarditis may include hospitalization with the administration of drugs to assist the heart, such as angiotensin-converting enzyme (ACE) inhibitors (enalapril, captopril, lisinopril, and Ramipril; angiotensin II receptor blockers (ARBs), such as losartan or valsartan; beta blockers, such as metoprolol, bisoprolol, and carvedilol; and diuretics, such as furosemide (Lasix). Additional treatments for patients with severe infectious myocarditis may include the use of ventricular assist devices (VADs), intra-aortic balloon pump, extracorporeal membrane oxygenation (ECMO), or emergency heart transplant. Patients with infectious myocarditis should avoid the use of non-steroidal anti-inflammatory drugs (NSAIDs) to prevent increased heart inflammation.