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. Key Features: Provides a detailed review of the unique challenges presented by young patients with small heart size, and patients of any age with distorted anatomy due to congenital heart disease, in this long overdue, updated text. Intends to guide all cardiologists engaged in invasive electrophysiology at both the training level and established practice who are exposed to such exceptional cases. Includes an internationally recognized group of experts who discuss the technical approaches, success rates, complication rates, and special precautions needed to achieve optimal outcomes.