This authoritative book explores electrophysiologic testing and therapeutic catheter ablation for cardiac arrhythmias in children, and in patients of all ages with congenital heart disease. It reviews the anatomic and physiologic background to these procedures, emphasizing the tools for mapping and tissue ablation that continue to improve patient outcomes. Additionally, individual chapters are dedicated to specific congenital heart defects (for instance, tetralogy of Fallot, Ebstein’s anomaly, univentricular heart) guiding the reader to anticipate the type of arrhythmia, the most likely location for effective ablation, and the technical challenges that may be encountered in each condition.