Transient high-grade heart block in a syncopal child with a normal outpatient cardiac evaluation

Heart block is an uncommon but serious cause of syncope in pediatric patients, and though autoimmune and infectious processes are often the cause, a rare subset of patients experience idiopathic childhood atrioventricular block. This report describes a transient high-grade heart block in a young child with a history of recurrent syncope, which was idiopathic despite an extensive outpatient evaluation. This case demonstrates the need to maintain a high index of suspicion for heart block or arrhythmia as a cause of syncope in pediatric patients.