Emergency department evaluation of an infant with chaotic atrial tachycardia.

We describe the diagnostic utility of adenosine infusion in an infant with chaotic atrial tachycardia. Transient blockade of the atrioventricular node during adenosine infusion added diagnostic certainty to the emergency department evaluation of this patient. Appropriate therapy for chaotic atrial tachycardia is controversial, so it is essential to differentiate this rhythm from more serious forms of supraventricular tachycardia in children.