Focal atrial tachycardias originate from different anatomic regions of the right atrium including the crista terminalis, the coronary sinus ostium, the tricuspid annulus, the interatrial septum and the right atrial appendage. The latter are characterized by being incessant and presenting poor response to antiarrhythmic treatment. They frequently evolve into tachycardiomyopathy and radiofrequency ablation is the treatment of choice. We present the case of a 36 month old girl with tachycardiomyopathy as a result of an incessant atrial tachycardia originated in the right atrial appendage. Patient underwent radiofrequency ablation.