Successful permanent pacemaker explantation after diagnosis and treatment of Lyme carditis complete heart block: a case report

Background: Lyme carditis (LC) complete heart block (CHB) is typically treated with i.v. antibiotics without requiring permanent pacing. In patients with high degree atrioventricular (AV) block, suspicious index in Lyme carditis (SILC) scoring is highly sensitive for diagnosing LC. Case summary: We present a case of CHB where a permanent pacemaker (PPM) was implanted prior to LC diagnosis. Suspicious index in Lyme carditis score was 2 at the time of exam, indicating a low risk for LC. However, per further discussion at follow-up, his score was retroactively increased to an intermediate risk of 4 and Lyme titres returned positive. An outpatient oral antibiotic regimen was given, and 2 months later, the patient had <0.1% V-pacing on interrogation with a subsequent unremarkable event monitor. The pacemaker was removed after considerations ensuring full conduction recovery. The patient is doing well at follow-up > 1 year. Discussion: Lyme carditis spontaneous resolution of CHB is common. Once safe extraction parameters have been established, it is appropriate to engage patients without ongoing pacer requirements about explantation of their PPM. For CHB patients without clear aetiology, SILC scoring may be a predictive measure to help prevent unnecessary PPM placement in the future.