What you need to know about Lyme carditis

Key Points for Healthcare Providers

  1. Ask all patients with suspected Lyme disease about cardiac symptoms, e.g., palpitations, chest pain, light headedness, fainting, shortness of breath, and difficulty breathing with exertion.
  2. Ask patients with acute, unexplained cardiac symptoms about possible tick exposure and symptoms of Lyme disease.
  3. Treat patients with suspected Lyme carditis with appropriate antibiotics immediately – do not wait for Lyme disease test results.
  4. Talk to patients about tick bite prevention.
Spirochetes in heart tissue. Image taken using Warthin-Starry stain at 158X magnification
Spirochetes in heart tissue. Image taken using Warthin-Starry stain at 158X.

What is Lyme carditis, and what are the symptoms?

Lyme carditis occurs when Lyme disease bacteria enter the tissues of the heart. This can interfere with the normal movement of electrical signals from the heart’s upper to lower chambers, a process that coordinates the beating of the heart. The result is something physicians call “heart block,” which can be mild, moderate, or severe. Heart block from Lyme carditis can progress rapidly.

Patients may experience light-headedness, fainting, shortness of breath, heart palpitations, or chest pain. Patients with Lyme carditis usually have other symptoms such as fever and body aches, and they may have more specific symptoms of Lyme disease, such as the erythema migrans rash. Early treatment of Lyme disease is important and can prevent complications.

How common is Lyme carditis?

Based on national surveillance data from 2001-2010, Lyme carditis occurs in approximately 1% of Lyme disease cases reported to CDC.

How is Lyme carditis treated?

Lyme carditis can be treated with oral or intravenous (IV) antibiotics, depending on how severe it is. Some patients might need a temporary pacemaker.

Can Lyme carditis be fatal?

Yes, between 1985 and 2019, eleven cases of fatal Lyme carditis have been reported in the medical literature.

How long does it take for a person to recover from Lyme carditis?

Typically the patient receives antibiotic treatment for 14-21 days. Most symptoms are gone within 1-6 weeks.

Third Degree Heart Block

The cross-section of the heart on the left shows the electrical signals as they flow through a normal heart. The drawing on the right shows where the electrical signal can become blocked, causing heart block

The heart on the left shows how an electrical signal flows from the atrioventricular node (AV node) to the chambers in the lower half of the heart, called the ventricles.

The heart on the right shows a case of third degree heart block. In this illustration, the electrical signal from the AV node to the ventricle is completely blocked. When this happens, the electrical signal of the atria (chambers at the top of the heart) does not transmit to the ventricles (chambers at the bottom of the heart), which causes the ventricles to beat at their own, slower rate.


Joseph D. Forrester, MD, MSc

Recognizing Lyme Carditisexternal icon
CDC Expert Commentary, January 2014

Additional Resources

For more information about heart block, including a video, see: What is Heart Block?external icon by the National Institutes of Health (NIH).

Fish AE, Pride YB, Pinto DS. Lyme carditis pdf icon[PDF – 14 pages]. Infect Dis Clin North Am. 2008 Jun;22(2):275-88, vi. [Reprinted with permission from Elsevier.]

Forrester JD, Meiman J, Mullins J, et al. Centers for Disease Control and Prevention (CDC). Notes from the field: update on Lyme carditis, groups at high risk, and frequency of associated sudden cardiac death–United States. MMWR Morb Mortal Wkly Rep. 2014 Oct 31;63(43):982-3.

Marx GE, Leikauskas J, Lindstrom K, et al. Fatal Lyme carditis in New England: Two case reportsexternal icon. Ann Intern Med. 2019 Oct 22. [Epub ahead of print]

Muehlenbachs A, Bollweg BC, Schulz TJ, et al. Cardiac tropism of Borrelia burgdorferi: An autopsy study of sudden cardiac death associated with Lyme carditis.external icon Am J Pathol. 2016 May;186(5):1195-205.