If the catheter is accurately targeted at the accessory pathway, the arrhythmia substrate will be destroyed. Significant complications of catheter ablation are rare. The main concern is production of atrioventricular block from ablation of pathways close to the normal conduction axis. Damage to the mitral and aortic valves is rare. Atrioventricular nodal reentry tachycardia becomes an increasing common arrhythmia during later childhood.
Drug treatment is often relatively ineffective or poorly tolerated.
Radiofrequency modification aims to destroy the posterior slowly conducting fibers while leaving the anterior fibers and the atrio-ventricular node unaffected. Atrial ectopic tachycardia in childhood will respond to drug treatment but spontaneous resolution in the long term is not very likely. Congenital junctional ectopic tachycardia is rare but is best treated by drugs because of the high risk of complete atrioventricular block associated with catheter ablation. Monomorphic ventricular tachycardia may arise in the left or right ventricle. Polymorphic ventricular tachycardia is rare but often dangerous.