Complete heart block due to lyme carditis.

Lyme carditis is becoming a more frequent complication of Lyme disease, primarily due to the increasing incidence of this disease in the United States. Cardiovascular manifestations of Lyme disease often occur within 21 days of exposure and include fluctuating degrees of atrioventricular (AV) block, acute myopericarditis or mild left ventricular dysfunction and rarely cardiomegaly or fatal pericarditis. AV block can vary from first-, second-, third-degree heart block, to junctional rhythm and asystolic pauses. Patients with suspected or known Lyme disease presenting with cardiac symptoms, or patients in an endemic area presenting with cardiac symptoms with no other cardiac risk factors should have a screening electrocardiogram along with Lyme titers. We present a case of third-degree AV block due to Lyme carditis, illustrating one of the cardiac complications of Lyme disease. This disease is usually self-limiting when treated appropriately with antibiotics, and does not require permanent cardiac pacing.