Lyme Carditis Identified by a Novel Syndromic Surveillance Definition, New York State, 2017-2021

Lyme carditis is a rare, potentially fatal manifestation of Lyme disease. Although Lyme disease is nationally notifiable, data on clinical manifestations are not collected systematically in the United States. We developed a syndromic surveillance definition to identify patients with Lyme carditis in New York State during 2017-2021.

We developed a definition of Lyme carditis by using diagnostic codes and keywords to identify emergency department visits related to Lyme carditis through the National Syndromic Surveillance Program's BioSense Platform. We systematically abstracted information for each identified patient by reviewing medical records in New York State's regional health information exchange system. Physician reviewers independently assigned a clinical case status to each record. We mapped cases of Lyme carditis by county and described their characteristics.

We identified records for 173 individuals; 32% (n = 55) were classified as confirmed, 16% (n = 27) as probable, and 53% (n = 91) as not a case of Lyme carditis. In total, we identified 82 cases of confirmed or probable Lyme carditis; the positive predictive value of the definition was 47%. Cases occurred in 49% of New York State counties and peaked annually in July and August. Among patients with confirmed and probable Lyme carditis, age distribution was bimodal, with incidence peaking at about ages 32 and 70 years; 71% were male. Eighty-four percent had positive 2-tiered serologic test results for Lyme disease, and second- or third-degree atrioventricular block was present in two-thirds of patients (67%).

This definition may be a useful tool to detect changing patterns of Lyme carditis in areas with a high incidence of Lyme disease.