Electrocardiogram Abnormalities in Children With Lyme Arthritis.

Background: Classically, Lyme disease follows a staged illness pattern with carditis occurring in early disseminated disease and arthritis in late-stage disease. A more comprehensive understanding of Lyme suggests that clinical stages may intersect. Little is known regarding the overlap of electrocardiogram (ECG) abnormalities in children with Lyme arthritis. This study aimed to estimate the prevalence of ECG changes in pediatric patients presenting with Lyme arthritis.

Methods: In this retrospective, cross-sectional study was conducted at a tertiary care children's hospital in a Lyme endemic area; patients were identified based on Lyme testing performed from January 2012 to August 2022. Children diagnosed with Lyme arthritis by 2-tiered serology with ECGs obtained within 2 days of antibiotic initiation were included. A study cardiologist reviewed all ECGs for evidence of carditis defined as atrioventricular block, ST-T wave changes, QTc interval prolongation, accelerated junctional rhythm or right bundle branch block.

Results: Two hundred thirty-three patients were diagnosed with Lyme arthritis; 90 (38.6%) had ECGs completed. Five patients (5.6%) had ECG abnormalities: 3 were diagnosed with first-degree atrioventricular block, 1 with QTc prolongation, and 1 with ST-T wave changes. No clinical or laboratory features in patients with Lyme arthritis were associated with an increased likelihood of having an abnormal ECG. All patients with ECG abnormalities were treated with oral antibiotics, and none had clinically significant cardiac disease.

Conclusions: ECG abnormalities in children with Lyme arthritis rarely occur and, when present, are not reflective of clinically significant cardiac disease. These results do not support routine screening ECGs on asymptomatic pediatric patients with Lyme arthritis.