RESUMEN
True emergencies due to unstable arrhythmias in children are rare, as most rhythm disturbances in this age group are well-tolerated. However, presentation to an emergency department with symptoms of palpitations, fatigue and/or syncope is much more common. Sinus tachycardia is by far the most commonly reported arrhythmia, followed by supraventricular tachycardia. Emergency physicians should be prepared for diagnosis and to acutely manage various types of arrhythmias seen in children, to assess the need for further diagnostic testing, and to determine whether cardiology evaluation and follow-up are needed. This article is intended to provide diagnostic and management guidelines of the most common types of arrhythmias seen in children with structurally normal hearts as well as those associated with congenital heart disease and cardiomyopathies.