Annals of Clinical Cardiology

: 2022  |  Volume : 4  |  Issue : 1  |  Page : 30--32

Electrocardiographic evolution of heart block in lyme carditis

Lubka B Ilieva, Essam Saad, Marc Iskandar, Peter A Brady 
 Advocate Illinois Masonic Medical Center, Chicago, Illinois, USA

Correspondence Address:
Dr. Lubka B Ilieva
Do, 202 W. Hill St, Apt 3407, Chicago, Illinois


A 23-year-old male presented with dizziness and weakness and reported travel to a tick-prevalent region 1 month prior. Initial electrocardiogram showed a high-grade atrioventricular block with narrow-complex escape rhythm, which progressed to a complete heart block with a wide-complex escape the next day. Resolution of the heart block was documented at follow-up after treatment with appropriate antibiotic therapy. Heart block in Lyme carditis is more commonly reported to be supra-Hisian, manifesting as a narrow-complex escape rhythm. Infra-Hisian block is rare, which manifests as a wide-complex escape rhythm, and may occasionally require permanent pacemaker implantation.

How to cite this article:
Ilieva LB, Saad E, Iskandar M, Brady PA. Electrocardiographic evolution of heart block in lyme carditis.Ann Clin Cardiol 2022;4:30-32

How to cite this URL:
Ilieva LB, Saad E, Iskandar M, Brady PA. Electrocardiographic evolution of heart block in lyme carditis. Ann Clin Cardiol [serial online] 2022 [cited 2023 May 29 ];4:30-32
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Full Text


Lyme carditis is a tick-borne illness leading to transient myocardial inflammation, causing varying degrees of atrioventricular block (AVB). Precise identification of the degree of AVB requires a high index of clinical suspicion and understanding of the pathophysiology to treat this reversible disease.

 Case Report

An otherwise healthy 23-year-old male presented with weakness and dizziness for 2 days. In addition, he reported camping in the rural areas of Minnesota and Buffalo, New York 1 month prior. He also noticed a rash that appeared on his left thigh about 2 weeks prior. Physical examination was remarkable for bradycardia of 44 beat/min and a rash on his left thigh [Figure 1]. Initial labs were significant for white blood cell count of 12.6 K/uL, and C-reactive protein elevated to 4.3 mg/L. Initial electrocardiogram (ECG) revealed high-grade AVB with a narrow-complex escape rhythm, suggestive of supra-Hisian involvement [Figure 2]. The patient was started on intravenous ceftriaxone. Transthoracic echocardiogram revealed a structurally normal heart. On day 2, Lyme antibody titer returned positive. As daily ECGs were acquired during his 6-day admission, we documented progression of the advanced AVB with narrow-complex escape rhythm to a complete heart block (CHB) with wide-complex escape rhythm the following day, raising concern for progression to infra-Hisian involvement [Figure 3]. As the patient remained stable and asymptomatic, temporary pacing was not required. On the 6th day of admission, ECG showed improvement of CHB to a first-degree AVB with a PR interval of 520 ms [Figure 4]. The patient was discharged home on oral doxycycline. At his follow-up in the clinic, a repeat ECG showed resolution of AV nodal conduction injury [Figure 5].{Figure 1}{Figure 2}{Figure 3}{Figure 4}{Figure 5}


Lyme disease is a tick-borne infection caused by Borrelia burgdorferi spread by its vector, the Ixodes scapularis tick. Transmission largely depends on the duration of attachment of the tick, whereby the highest risk occurs on the 3rd day of attachment.[1] The disease occurs in three stages. The first early infection stage is marked by the characteristic bulls-eye rash of erythema migrans, which usually fades in 3–4 weeks, along with constitutional symptoms. In the second dissemination stage, the pathogen spreads to the bloodstream, leading to secondary annular skin lesions alongside episodic migratory joint pains and headaches. The most common reported symptom in the second stage is fatigue. Only 4%–8% of patients during this stage will have cardiac involvement manifesting as fluctuating degrees of atrioventricular AVB, which are brief, lasting from 3 days to 6 weeks. Rarely does the AV block persist; thus, a permanent pacemaker is not usually indicated. The third stage is the persistent infection stage, where the patient will have prolonged arthritis symptoms with chronic encephalomyelitis.[1] According to the Centers for Disease Control and Prevention, demonstration of immunoglobulin M antibodies against B. burgdorferi and one late manifestation of the disease involving an affected organ system are sufficient for making the diagnosis. In the setting of Lyme carditis, the Infectious Disease Society of America recommends hospitalization and treatment with parenteral antibiotics initially, such as ceftriaxone, until resolution of high-grade AVB, after which the patient can be discharged to complete a 21-day course of oral antibiotics, such as doxycycline.[1]

Lyme carditis occurs due to transient myocardial inflammation, causing varying degrees of AVB. It usually occurs around 4 weeks after infection, in a patient exposed to a tick-prevalent region.[1] The inflammation primarily affects the AV node and, depending on its location, it can have various ECG findings. In the more common supra-Hisian involvement, the patients will typically have narrow QRS escape complexes, whereas infra-Hisian involvement manifests as a wide-complex escape rhythm.[2] In a study of three patients, electrophysiologic studies alongside endomyocardial biopsies were performed on patients presenting with varying degrees of AV block secondary to Lyme carditis. One of the patients had no terminal negative deflection in the His spike accompanied by a regular AH interval and there was no relationship between the His bundle and ventricular complex, suggesting a block in the distal His bundle, leaving the proximal bundle undisturbed. In this patient, a complete AV block persisted despite extensive antibiotics and steroid treatment and required a permanent pacemaker.


Lyme-related heart block is a rare condition with a broad clinical spectrum ranging from resolution to requiring pacemaker implantation. Aside from prompt antibiotic initiation, careful evaluation of ECG progression can predict the clinical course. Supra-Hisian involvement is most common and is usually reversible. On the other hand, infra-Hisian involvement is rare and can be permanent. Our patient presented with a narrow-complex escape rhythm, suggestive of supra-Hisian involvement, which evolved into a wide-complex QRS escape the following day, suggesting progression of inflammation and conduction system injury to include the infra-Hisian bundle. With appropriate antibiotic treatment, the ECGs over the next 2 weeks revealed progressive resolution of conduction system injury.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.


1Steere A. Lyme disease. N Engl J Med 1989;321:586-96.
2van der Linde MR, Crijns HJ, de Koning J, Hoogkamp-Korstanje JA, de Graaf JJ, Piers DA, et al. Range of atrioventricular conduction disturbances in Lyme borreliosis: A report of four cases and review of other published reports. Br Heart J 1990;63:162-8.