Tachyarrhythmias are common cardiac arrhythmias in newborns and infants. We present a premature case with a 2.4-kg birth weight, with non-immune hydrops due to supraventricular tachycardia. Despite the combination of amiodarone, esmolol and flecainide, tachyarrhythmia could not be controlled and radiofrequency ablation was applied due to left ventricular dysfunction. After the procedure the rhythm returned to normal sinus and left ventricular functions improved rapidly. The follow-up of the case continues without any problems. In this presentation, successful ablation of the accessory pathway associated with structural heart disease have been covered in the youngest and smallest patient to date.

Keywords: left atrial appendage aneurysm, newborn, radiofrequency ablation, supraventricular tachycardia