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 approach, success rate, complication rate, and special precautions needed to achieve optimal outcomes.