Supraventricular microreentry in a newborn due to a giant atrial septum aneurysm.

Supraventricular arrhythmias in neonates are rare and mostly not related to structural heart defects. We present the first case of a newborn with a supraventricular microreentrant tachycardia possibly associated with an atrial septum aneurysm and emphasize the importance of a thorough diagnostic workup allowing a fast and adequate therapy.