The field of arrhythmias in children has recently seen major advances in several aspects, including diagnosis (event monitoring systems) and treatment (very effective acute and longterm medications) and, more importantly, in the definitive cure of supraventricular tachycardia with the use of catheter ablation techniques. These procedures are very successful and can be performed with a low complication rate. The indications for radiofrequency ablation are expanding and the technical aspects improving rapidly, so a larger number of patients will benefit from this curative treatment.