Flutter and atrial fibrillation are extremely rare in children. Their aetiology and pathogenesis vary from one case to another. The clinical picture may be influenced by a number of factors (age, duration of the arrhythmia, ventricular frequency), while the natural history is often related to the presence or otherwise of associated cardiopathies. There is no standard treatment. Digitalis with or without other antiarrhythmic drugs is often employed as the drug of choice, though its place may be taken by ayodarone or verapamil.