[Congenital heart defects in adulthood : Supraventricular tachycardia]

Supraventricular tachycardia (SVT) based on congenital substrates, such as accessory pathways or dual atrioventricular nodal properties, occur with an increased probability linked to specific congenital heart defects (CHDs). In the literature, the association of Ebstein's anomaly with accessory pathways and with Mahaim fibers is most prominent. Compared with patients with otherwise normal hearts, the clinical relevance of SVT is typically more severe and therefore antiarrhythmia treatment is a necessity in many cases. Diagnostics, pharmaceutical treatment, and interventional therapy of SVT in patients with CHD are often demanding owing to anatomical, hemodynamic, and electro-anatomical peculiarities. The use of antiarrhythmic medication is often limited because of intolerable side effects and a lack of reliability in suppressing arrhythmia relapses in the long term. Within the last 15-20 years catheter ablation has thus become established as the first-choice treatment for SVT, even in patients with CHD. However, rates of success, recurrence, and risks are still inferior to those observed in patients with a normally functioning heart owing to the co-existence of vascular and cardiac anomalies, surgically created alterations, an unusual electro-anatomy, and lower tolerance to hemodynamic changes. Successful treatment in patients with CHDs and SVT requires a deep understanding and knowledge of all the disciplines discussed above and should only be practiced in dedicated centers, as patient numbers are small and therefore experience is limited.