Junctional ectopic tachycardia secondary to myocarditis associated with sudden cardiac arrest☆

Lyme disease has been associated with junctional ectopic tachycardia (JET) and fascicular tachycardia in the past; however, we believe this case report is the first known reported case of a patient with Lyme disease presenting as fulminant myocarditis and cardiac arrest. Our patient is a previously healthy 12-year-old male subject who presented with cardiac arrest and JET, ultimately secondary to fulminant myocarditis from Lyme disease. With antibiotic and antiarrhythmic treatment, sinus rhythm returned, and ultimately he had full recovery of his cardiac function. His initial cardiac magnetic resonance imaging (MRI) showed diffuse delayed gadolinium enhancement along the interventricular septum, with near resolution 5 weeks later on repeat imaging. It is likely that edema and/or inflammation near the His bundle resulted in JET.