The survival of patients with congenital heart disease (CHD) has increased immensely and nowadays, most children reach adulthood. The long-term outcome is hampered by the occurrence of late complications such as arrhythmias. Supraventricular and ventricular arrhythmias have an impact notably not only on morbidity but also on mortality in patients with congenital heart disease. Therefore, life-long follow-up in most of these patients is required.