Heart Inflammation - Causes - Causes

Heart inflammation can be caused by infections, particularly from viruses or bacteria; medicines; or damage to the heart’s tissue or muscle from autoimmune diseases, medicines, environmental factors, or other triggers. The causes of heart inflammation may vary depending on the part of the heart that is affected—the endocardium, the myocardium, or the pericardium.

Infections

Viral, bacterial, and fungal infections can cause heart inflammation.

  • Viral infections are the most common cause of myocarditis and pericarditis. These may include adenovirus, coxsackievirus, herpes virus, influenza (flu) virus, and parvovirus B19. Viruses may infect the heart muscle tissue, causing acute or chronic immune responses from the body. Watch our video on how SARS-CoV-2, the virus responsible for COVID-19, may affect your heart. Additionally, we offer information and resources on how we are working hard to support necessary COVID-19 research.
  • Bacteria are the most common cause of endocarditis, which occurs when bacteria and blood cells form clumps, typically on the heart valves. In most developed countries Staphylococcus aureus is the most common type of bacteria that causes endocarditis. Bacteria can enter the blood during invasive medical procedures or intravenous drug use. Streptococcus bacteria can also cause endocarditis, but this is more common in less developed countries. Pericarditis caused by bacteria is rare in the United States and other developed countries. However, in developing countries, 70 percent of pericarditis cases are caused by Mycobacterium tuberculosis, the organism that causes tuberculosis.
  • Fungi are rare causes of myocarditis and pericarditis. Most commonly, fungal endocarditis is caused by either Candida or Aspergillus. These infections are more common in immunosuppressed patients, including those who have HIV.
  • Other infections. Another infectious cause of myocarditis includes the parasite that causes Chagas disease, which is a serious health problem in Latin America. The parasite can specifically affect the heart at the time of infection and may lead to the need for a pacemaker.

How do viruses cause myocarditis?

Viruses may infect the cells of the heart tissue. Once the virus is in the cell, the virus multiplies and activates the body’s immune system, leading to damage in the heart tissue. This initial phase of infection can last weeks to months.

If the viral infection lasts for a long time, it can damage the structure and function of the heart muscle and may lead to dilated cardiomyopathy.

Autoimmune diseases

Autoimmune diseases such as rheumatoid arthritis and lupus erythematosus may cause pericarditis or myocarditis. They can also damage the heart valves, which can lead to endocarditis.

Medicines

Medicines can cause side effects that may lead to myocarditis, pericarditis, or both. These medicines include:

  • Antibiotics, such as penicillin
  • Antidepressants, such as tricyclic antidepressants
  • Benzodiazepines, known as tranquilizers, such as lorazepam and diazepam
  • Diuretics, which are medicines, such as furosemide and hydrochlorothiazide, that help your body get rid of fluid
  • Heart medicines, such as amiodarone, hydralazine, methyldopa, and procainamide
  • Psychiatric medicines, such as clozapine and lithium
  • Seizure medicines, such as phenytoin
  • Vaccines, which may cause allergic reactions leading to myocarditis, although this is rare
  • Weight-loss medicines, such as phentermine-fenfluramine or phen-fen

Environmental factors

Environmental factors that may cause myocarditis include:

  • Heavy metals, such as copper and lead
  • Radiation

Look for

  • Treatment will discuss the medicines or procedures that your doctors may recommend if you are diagnosed with heart inflammation—endocarditis, myocarditis, or pericarditis.