A 12-year-old girl presented with fever and signs of systemic inflammation, and was found to have junctional tachycardia. She was subsequently diagnosed with Multisystem Inflammatory Syndrome in Children and treated with intravenous immunoglobulin and steroids, which led to resolution of the arrhythmia.

Accelerated junctional rhythm has been reported in children in the setting of acute rheumatic fever; however, we describe a hitherto unreported case of isolated junctional tachycardia in a child with streptococcal pharyngitis, not meeting revised Jones criteria for rheumatic fever. A previously healthy, 9-year-old girl presented to the emergency department with complaints of sore throat, low-grade fever, and intermittent chest pain. She was found to have a positive rapid streptococcal antigen test. The initial electrocardiogram showed junctional tachycardia with atrioventricular dissociation in addition to prolonged and aberrant atrioventricular conduction. An echocardiogram revealed normal cardiac anatomy with normal biventricular function. The patient responded to treatment with amoxicillin for streptococcal pharyngitis. The junctional tachycardia and other electrocardiogram abnormalities resolved during follow-up.