Junctional ectopic tachycardia is a common dysrhythmia after congenital heart surgery that is associated with increased perioperative morbidity and mortality. Risk factors for development of junctional ectopic tachycardia include young age (neonatal and infant age groups); hypomagnesemia; higher-complexity surgical procedure, especially near the atrioventricular node or His bundle; and use of exogenous catecholamines such as dopamine and epinephrine. Critical care nurses play a vital role in early recognition of dysrhythmias after congenital heart surgery, assessment of hemodynamics affecting cardiac output, and monitoring the effects of antiarrhythmic therapy. This article reviews the underlying mechanisms of junctional ectopic tachycardia, incidence and risk factors, and treatment options. Currently, amiodarone is the pharmacological treatment of choice, with dexmedetomidine increasingly used because of its anti-arrhythmic properties and sedative effect.