Atrial fibrillation in a preterm newborn with structurally normal heart.

Atrial fibrillation (AF) is a really uncommon arrhythmia in newborns. Here, we report the case of a 1-day-old infant who was recovered in Neonatal Intensive Care Unit for a twin-to-twin transfusion. The appearance of an unexpected AF was registered at his continuous electrocardiographic monitoring. Both chest X-ray and echocardiographic examination revealed the anomalous insertion of the tip of a central venous catheter (CVC) into the heart ('umbilical artery → inferior vena cava → right atrium → patent foramen ovale → left atrium'). AF ceased as soon as the CVC was extracted from the heart. The mechanical irritation of both atria caused by the malposition of the CVC might be the underlying mechanism responsible for the triggering of AF in this unique case report.